The history of railways ( )

      The history of railways



     The railway is  good example of  system evolved in variousplaces to
fulfil  need and then developed empirically. In essence it consists f
parallel tracks or bars of metal or wood, supported transversely by other
bars  stone, wood, steel and concrete have been used  so that th load of
the vehicle is spread evenly through the substructure. Such tracks were
used in the Middle Ages for mining tramways in Europe; railways came to
England in the 16th century and went back to Europe in the 19th century as
an English invention.



                    English railways



    The first Act of Parliament for  railway, giving right of way over
other people's property, was passed
in 1758, and the first for  public railway, to carry the traffic of all
comers, dates from 1801. The Stockton and Dailington Railway, opened on 27
September 1825, was the first public steam railway in the world, although
it had only one locomotive and relied on horse traction for the most part,
with stationary steam engines for working inclined planes.
    The obvious advantages of railways as  means of conveying heavy loads
and passengers brought about  proliferation of projects. The Liverpool &
Manchester, 30 miles (48 km) long and including formidable engineering
problems, became the classic example of  steam railway for general
carriage. It opened on 15 September 1830 in the presence of the Duke of
Wellington, who had been Prime Minister until earlier in the year. On
opening day, the train stopped for water and the passengers alighted on to
the opposite track; another locomotive came along and William Huskisson, an
 and  great advocate of the railway, was killed. Despite this tragedy
the railway was  great success; in its first year of operation, revenue
from passenger service was more than ten times that anticipated. Over 2500
miles of railway had been authorized in Britain and nearly 1500 completed
by 1840.
    Britain presented the world with  complete system for the construction
and operation of railways. Solutions were found to civil engineering
problems, motive power designs and the details of rolling stock. The
natural result of these achievements was the calling in of British
engineers to provide railways in France, where as  consequence left-hand
rujning is still in force over many lines.



                    Track gauges



    While the majority of railways in Britain adopted the 4 ft 8.5 inch
(1.43 m) gauge of the Stockton &
Darlington Railway, the Great Western, on the advice of its brilliant but
eccentric engineer Isambard Kingdom Brunel, had been laid to  seven foot
(2.13 m) gauge, as were many of its associates. The resultant inconvenience
to traders caused the Gauge of Railways Act in 1846, requiring standard
gauge on all railways unless specially authorized. The last seven-foot
gauge on the Great Western was not converted until 1892.
    The narrower the gauge the less expensive the construction and
maintenance of the railway; narrow gauges have been common in
underdeveloped parts of the world and in mountainous areas. In 1863 steam
traction was applied to the 1 ft 11.5 inch (0.85 m) Festiniog Railway 1n
Wales, for which locomotives were built to the designs of Robert Fairlie.
 then led  campaign for the construction of narrow gauges. As  result
of the export of English engineering and rolling stock, however, most North
American and European railways have been built to the standard gauge,
except in Finland and Russia, where the gauge is five feet (1.5 m).



                    Transcontinental lines



The first public railway was opened in America in 1830, after which rapid
development tookplace.  famous 4-2-0 locomotive called the Pioneer first
ran from Chicago in 1848, and that city became one of the largest rail
centres in the world. The Atlantic and the Pacific oceans were first linked
on 9  1869, in  famous ceremony at the meeting point of the Union
Pacific and Central Pacific lines at Promontory Point in the state of Utah.
Canada was crossed by the Canadian Pacific in 1885; completion of the
railway was  condition of British Columbia joining the Dominion of Canada,
and considerable land concessions were granted in virtually uninhabited
territory.
    The crossing of Asia with the Trans-Siberian Railway was begun by the
Russians in 1890 and completed in 1902, except for  ferry crossing Lake
Baikal. The difficult passage round the south end of the lake, with many
tunnels, was completed in 1905. Today more than half the route is
electrified. In 1863 the Orient Express ran from Paris for the first time
and eventually passengers were conveyed all the way to Istanbul
(Constantinople).



                    Rolling stock



In the early days, coaches were constructed entirely of wood, including the
frames.  1900, steel frames were commonplace; then coaches were
constructed entirely of steel and became very heavy. One American 85-foot
(26 m) coach with two six-wheel bogies weighed more than 80 tons. New
lightweight steel alloys and aluminium began
to be used; in the 1950s the Budd company in America was
building an 85-foot coach which weighed only 27 tons. The savings began
with the bogies, which were built without conventional springs, bolsters
and so on; with only two air springs on each four-wheel bogie, the new
design reduced the weight from 8 to 2,5 tons without loss f strength or
stability.
    In the I880s, 'skyscraper' cars were two-storey wooden vans with
windows used as travelling dormitories for railway workers in the USA; they
had to be sawn down when the railways began to build tunnels through the
mountains. After World War II double-decker cars of  mr compact design
were built, this time with plastic domes, so that passengers could enjoy
the spectacular scenery on the western lines, which pass through the Rocky
Mountains.
    Lighting on coaches was by means of oil lamps at first; then gas lights
were used, and each coach carried  cylinder f gas, which was dangerous in
the event of accident or derailment. Finally dynamos on each car, driven by
the axle, provided electricity, storage batteries being used for when the
car was standing. Heating on coaches was provided in the early days
by metal containers filled with hot water; then steam was piped from the
locomotive, an extra drain on the engine's power; nowadays heat as well as
light is provided electrically.
    Sleeping accommodations were first made on the Cumberland Valley
Railroad in the United States in 1837. George Pullman's first cars ran on
the Chicago & Alton Railroad in 1859 and the Pullman Palace Car Company was
formed in 1867. The first Pullman cars operated in Britain in 1874,  year
after the introduction of sleeping cars by two British railways. In Europe
in 1876 the International Sleeping Car Company was formed, but in the
meantime George Nagelmackers of Liege and an American, Col William D'Alton
nn, began operation between Paris and Viennain 1873.
    Goods vans [freight cars] have developed according to the needs of the
various countries. On the North American continent, goods trains as long as
1,25 miles are run as far as 1000 miles unbroken, hauling bulk such as raw
materials and foodstuffs. Freight cars weighing 70 to 80 tons have two four
wheel bogies. In Britain, with  denser population and closely adjacent
towns,  large percentage of hauling is of small consignments of
manufactured goods, and the smallest goods vans of any country are used,
having four wheels and, up to 24,5 tons capacity.  number of bogie wagons
are used for special purposes, such as carriages fr steel rails, tank cars
for chemicals and 50 ton brick wagons.
    The earliest coupling system was links and buffers, which allowed jerky
stopping and starting. Rounded buffers brought snugly together by
adjustment of screw links with springs were an improvement. The buckeye
automatic coupling, long standard in North America, is now used in Britain.
The coupling resembles  knuckle made of steel and extending horizontally;
joining utomtika11 with the coupling of the next r when pushed
together, it is released by pulling  pin.
    The first shipment of refrigerated goods was in 1851 when butter was
shipped from New York to Boston in  wooden van packed with ice and
insulated with sawdust. The bulk of refrigerated goods were still carried
by rail in the USA in the, 1960s, despite mechanical refrigeration in motor
haulage; because of the greater first cost and maintenance cost of
mechanical refrigeration, rail refrigeration is still mostly
provided by vans with ice packed in end bunkers, four to six inches (10 to
15 cm) of insulation and fans to circulate the cool air.



                    Railways in wartime



    The first war in which railwaysfigured prominently
was the American Civil War (1860-65), in which the Union
(North) was better able to organize andmake use of its railways than the
Confederacy (South). The war was marked by  famous incident in which  4-4-
0 locomotive
called the General was hi-jacked by Southern agents.
   The outbreak of World War 1 was caused in part by the
fact that the mobilization plans of the various countries, including the
use f railways and rolling stock, was planned to the last detail, except
that there were n provisions for stopping the plans once they had been put
into action until the armies were facing each other. In 1917 in the United
States, the lessons of the Civil War had been forgotten, and freight vans
were sent to their destination with n facilities for unloading, with the
result that the railways were briefly taken over by the government for the
only time in that nation's history.
    In World War 2, by contrast, the American railways performed
magnificently, moving 2,5 times the level of freight in 1944 as in 1938,
with minimal increase in equipment, and supplying more than 300,000
employees to the armed forces in various capacities. In combat areas, and
in later conflicts such as the Korean war, it proved difficult to disrupt
an enemy's rail system effectively; pinpoint bombing was difficult,
saturation bombing was expensive and in any case railways were quickly and
easily repaired.



                    State railways



    State intervention began in England withpublic demand for safety
regulation which resulted in Lord
Seymour's Act in 1840; the previously mentioned Railway
Gauges Act followed in 1846. Ever since, the railways havebeen recognized
as one of the most important of nationalresources in each country.
    In France, from 1851 onwards concessions were granted for a planned
regional system for which the Government provided ways and works and the
companies provided track and roiling stock; there was provision for the
gradual taking over of the lines by the State, and the Societe Nationale
des Chemins de Fer Francais (SNCF) was formed in 1937 as  company in which
the State owns 51% of the capital and theompanies 49%.
    The Belgian Railways were planned by the State from the outset in 1835.
The Prussian State Railways began in 1850; b the end of the year 54 miles
(87 km) were open. Italian and Netherlands railways began in 1839; Italy
nationalized her railways in 1905-07 and the Netherlands in the period 1920-
38. In Britain the main railways were nationalized from 1 January 1948; the
usual European pattern is that the State owns the main lines and minor
railways are privately owned or operated by local authorities.
    In the United States, between the Civil War and World Wr 1 the
railways, along with all the other important inndustries, experienced
phenomenal growth as the country developed. There were rate wars and
financial piracy during  period of growth when industrialists were more
powerful than the national government, and finally the Interstate Commerce
Act was passed in l887 in order to regulate the railways, which had  near
monopoly of transport. After World War 2 the railways were allowed to
deteriorate, as private car ownership became almost universal and public
money was spent on an interstate highway system making motorway haulage
profitable, despite the fact that railways are many times as efficient at
moving freight and passengers. In the USA, nationalization of railways
would probably require an amendment to the Constitution, but since 1971 
government effort has been made to save the nearly defunct passenger
service. On 1 May of that year Amtrack was formed by the National Railroad
Passenger Corporation to operate  skeleton service of 180 passenger trains
nationwide, serving 29 cities designated by the government as those
requiring train service. The Amtrack service has been heavily used, but
not adequately funded by Congress, so that bookings,
especially for sleeper-car service, must be made far in
advance.



                    The locomotive



    Few machines in the machine age have inspired so much affection as
railway locomotives in their 170 years of operation. Railways were
constructed in the sixteenth century, but the wagons were drawn by muscle
power until l804. In that year an engine built by Richard Trevithick worked
on the Penydarren Tramroad in South Wales. It broke some cast iron
tramplates, but it demonstrated that steam could be used for haulage, that
steam generation could be stimulated by turning the exhaust steam up the
chimney to draw up the fire, and that smooth wheels on smooth rails could
transmit motive power.



                    Steam locomotives



    The steam locomotive is  robust and
simple machine. Steam is admitted to  cylinder and by
expanding pushes the piston to the other end; on the return stroke  port
opens to clear the cylinder of the now expanded steam. By means of
mechanical coupling, the travel of the piston turns the drive wheels of the
locomotive.
    Trevithick's engine was put to work as  stationary engine at
Penydarren. During the following twenty-five years,  limited number of
steam locomotives enjoyed success on colliery railways, fostered by the
soaring cost of horse fodder towards the end of the Napoleonic wars. The
cast iron plateways, which were L-shaped to guide the wagon wheels, were
not strong enough to withstand the weight of steam locomotives, and were
soon replaced by smooth rails and flanged wheels on the rolling stock.
    John Blenkinsop built several locomotives for collieries, which ran on
smooth rails but transmitted power from  toothed wheel to  rack which ran
alongside the running rails. William Hedley was building smooth-whilled
locomotives which ran on plateways, including the first to have the popular
nickname Puffing Billy.
    In 1814 George Stephenson began building for smooth rails at
Killingworth, synthesizing the experience of the earlier designers. Until
this time nearly all machines had the cylinders partly immersed in the
boiler and usually vertical. In 1815 Stephenson and Losh patented the idea
of direct drive from the cylinders by means of cranks on the drive wheels
instead of through gear wheels, which imparted  jerky motion, especially
when wear occurred on the coarse gears. Direct drive allowed  simplified
layout and gave greater freedom to designers.
    In 1825 only 18 steam locomotives were doing useful work. One of the
first commercial railways, the Liverpool & Manchester, was being built, and
the directors had still not decided between locomotives and bl haulage,
with railside steam engines pulling the cables. They organized 
competition which was won by Stephenson in 1829, with his famous engine,
the Rocket, now in London's Science Museum.
    Locomotive boilers had already evolved from  simple
flue to  return-flue type, and then to  tubular design, in which  nest
of fire tubes, giving more heating surface, ran from the firebox tube-plate
to  similar tube-plate at the smokebox end. In the smokebox the exhaust
steam from the cylinders created  blast on its way to the chimney which
kept the fire up when the engine was moving. When the locomotive was
stationary  blower was used, creating  blast from  ring f perforated
pipe into which steam was directed.  further development, the multitubular
boiler, was patented by Henry Booth, treasurer of the Liverpool &
Manchester, in 1827. It was incorporated by Stephenson in the Rocket, after
much trial and error in making the ferrules of the copper tubes to give
water-tight joints in the tube
plates.
    After 1830 the steam locomotive assumed its familiar form, with the
cylinders level or slightly inclined at the smokebox end and the fireman's
stand at the firebox end.
    As soon as the cylinders and axles were n longer fixed in or under the
boiler itself, it became necessary to provide  frame to hold the various
components together. The bar frame was used on the early British
locomotives and exported  to America; the Americans kept  the bar-frame
design, which evolved from wrought iron to cast steel construction, with
the cylinders mounted outside the frame. The bar frame was superseded in
Britain by the plate frame, with cylinders inside the frame, spring
suspension (coil or laminated) for the frames and axleboxes (lubricated
bearings) to hold the
axles.
    As British railways nearly all produced their own designs,  great many
characteristic types developed. Some designs with cylinders inside the
frame transmitted the motion to crank-shaped axles rather than to eccentric
pivots on the outside of the drive wheels; there were also compound
locomotives, with the steam passing from  first cylinder or cylinders to
another set of larger ones.
    When steel came into use for building boilers after 1860, higher
operating pressures became possible. By the end of the nineteenth century
175 psi (12 bar) was common, with 200 psi (13.8 bar) for compound
locomotives. This rose to 250 psi (17.2 bar) later in the steam era. (By
contrast, Stephenson's Rocket only developed 50 psi, 3.4 bar.) In the l890s
express engines had cylinders up to 20 inches (51 cm) in diameter with  26
inch (66 cm) stroke. Later diameters increased to 32 inches (81 cm) in
places like the USA, where there was more room, and locomotives and rolling
stock in general were built larger.
    Supplies of fuel and water were carried on  separate tender, pulled
behind the locomotive. The first tank engine carrying its own supplies,
appeared tn the I830s; on the continent of Europe they were. confusingly
called tender engines. Separate tenders continued to be common because they
made possible much longer runs. While the fireman stoked the firebox, the
boiler had to be replenished with water by some means under his control;
early engines had pumps running off the axle, but there was always the
difficulty that the engine had to be running. The injector was invented in
1859. Steam from the boiler (or latterly, exhaus  steam) went through 
cone-shaped jet and lifted the water into the boiler against the greater
pressure there through energy imparted in condensation.  clack (non-return
valve)
retained the steam in the boiler.
    Early locomotives burned wood in America, but coal in Britain. As
British railway Acts began to include penalties for emission of dirty black
smoke, many engines were built after 1829 to burn coke. Under Matthetty
Kirtley on the Midland Railway the brick arch in the firebox and deflector
plates were developed to direct the hot gases from the coal to pass over
the flames, so that  relatively clean blast came out of
the chimney and the cheaper fuel could be burnt. After 1860 this simple
expedient was univers11 adopted. Fireboxes were protected by being
surrounded with  water jacket; stays about four inches (10 cm) apart
supported the inner firebox from the outer.
    Steam was distributed to the pistons by means of valves. The valve gear
provided for the valves to uncover the ports at different parts of the
stroke, so varying the cut-off to provide for expansion of steam already
admitted to the cylinders and to give lead or cushioning by letting the
steam in about 0.8 inch (3 mm) from the end of the stroke to begin the
reciprocating motion again. The valve gear also provided for reversing by
admitting steam to the opposite side of the piston.
    Long-lap or long-travel valves gave wide-open ports for the exhaust
even when early cut-ff was used, whereas with short travel at early cut-
off, exhaust and emission openings became smaller so that at speeds of over
60 mph (96 kph) one-third of the ehergy of the steam was expanded just
getting in and out of the cylinder. This elementary fact was not
universal1y
accepted until about 1925 because it was felt that too much extra wear
would occur with long-travel valve layouts.
    Valv operation on most early British locomotives was by Stephenson
link motion, dependent on two eccentrics on the driving 1 connected by
rods to the top and bottom of an expansion link.  block in the link,
connected to the reversing lever under the control of the driver, imparted
the reciprocating motion t the valve spindle. With the block at the top of
the link, the engine would be in full forward gear and steam would be
admitted to the cylinder for perhaps 75% of the stoke. As the engine was
notched up by moving the lever back over its serrations (like the handbrake
lever of  r), the cut-off was shortened; in mid-gear there was no steam
admission to the cylinder and with the block at the bottom of the link the
engine was in full reverse.
    Walschaert's valvegear, invented in 1844 and in general use after 1890,
allowed more precise adjustment and easier operation  for the driver. An
eccentric rod worked from  return crank by the driving axle operated the
expansion link; the block imparted the movement to the valve spindle, but
the movement was modified by  combination lever from  crosshead on the
piston rod.
    Steam was collected as dry as possible along the top of the boiler in 
perforated pipe, or from  point above the boiler in  dome, and passed to
 regulator which controlled its distribution. The most spectacular
development of steam locomotives for heavy haulage and high speed runs was
the introduction of superheating.  return tube, taking the steam back
towards the firebox and forward again to  header at the front end of the
boiler through an enlarged flue-tube, was invented by Wilhelm Schmidt of
Cassel, and modified by other designers. The first use of such equipment in
Britain was in 1906 and immediately the savings in fuel and especially
water were remarkable. Steam at 175 psi, for example, was generated
'saturated' at 371'F (188'); by adding 200'F (93'C) of superheat, the
steam expanded much more readily in the cylinders, so that twentieth-
century locomotives were able to work at high speeds at cut-offs as short
as 15%. Steel tyres, glass fibre boiler lagging, long-lap piston valves,
direct steam passage and superheating all contributed to the last
phase of steam locomotive performance.
    Steam from the boiler was also for other purposes.
Steam sanding was introduced for traction in 1887 on th
Midland Railway, to improve adhesion better than gravity
sanding, which often blew away. Continuous brakes were
operated by  vacuum created on the engine or by mpressed air supplied by
 steam pump. Steam heat was piped to the carriages, arid steam dynamos
[generators] provided electric light.
    Steam locomotives are classified according to the number of wheels.
Except for small engines used in marshalling rds, all modern steam
locomotives had leading wheels on a pivoted bogie or truck to help guide
them around urves. The trailing wheels helped carry the weight of the
firebox. For many years the 'American standard' locomotive was a 4-4-0,
having four leading wheels, four driving wheels and no trailing wheels. The
famous Civil War locomotive, the General, was  4-4-0, as was the New York
Central Engine No 999, which set  speed record 1 112.5 mph (181 kph) in
1893. Later,  common freight locomotive configuration was the Mikado type,
 2-8-2.
     Continental classification counts axles instead f wheels, and
another modification gives drive wheels  letter of the alphabet, so the 2-
8-2 would be 1-4-1 in France and IDI in Germany.
    The largest steam locomotives were articulated, with two sets of drive
wheels and cylinders using  common boiler. The sets f drive wheels were
separated by  pivot; otherwise such  large engine could not have
negotiated curves. The largest ever built was the Union Pacific Big o, 
4-8-8-4, used to haul freight in the mountains of the western United
States. Even though it was articulated it could not run on sharp curves. It
weighed nearly 600 tons, compared to less than five tons for Stephenson's
Rocket.
    Steam engines could take  lot of hard use, but they are now obsolete,
replaced by electric and especially diesel-electric locomotives. Because of
heat losses and incomplete combustion of fuel, their thermal efficinc was
rarely more than 6%.



                    Diesel locomotives



    Diesel locomotives are most commonly diesel-electric.  diesel engine
drives  dynamo [generator] which provides power for electric motors which
turn the
drive wheels, usually through  pinion gear driving  ring gear on the
axle. The first diesel-electric propelled rail car was built in 1913, and
after World War 2 they replaced steam engines completely, except where
electrification of railways is economical.
    Diesel locomotives have several advantages over steam engines. They are
instantly ready for service, and can be shut down completely for short
eriods, whereas it takes some time to heat the water in the steam engine,
especially in cold weather, and the fire must be kept up while the steam
engine is on standby. The diesel can go further without servicing, as it
consumes n water; its thermal efficiency is four times as high, which
means further savings of fuel. Acceleration and
high-speed running are smoother with  diesel, which means less wear on
rails and roadbed. The economic reasons for turning to diesels were
overwhelming after the war, especially in North America, where the railways
were in direct competition with road haulage over very long distances.



                    Electric traction



    The first electric-powered rail car was built in 1834, but early
electric cars were battery powered, and the batteries were heavy and
required frequent recharging. d 1tri trains are not self-contained,
which means that they get their power from overhead wires or from  third
rail. The power for the traction motors is collected from the third rail
by means of  shoe or from the overhead wires by  pantograph.
    Electric trains are the most nomical to operate,
provided that traffic is heavy enough to repay electrification of the
railway. Where trains run less frecuentl over long distances the cost of
electrification is prohibitive. DC systems have been used as opposed to 
because lighter traction motors can be used, but this requires power
substations with rectifiers to convert the power to D from the  of the
commercial mains. (High voltage DC power is difficult to transmit over long
distances.) The latest development
of electric trains has been the installation of rectifiers in the cars
themselves and the use of the same  frequency as the commercial mains (50
Hz in Europe, 60 Hz in North America),which means that fewer substations
are necessary.



                    Railway systems



    The foundation of  modern railway system is track which does not
deteriorate under stress of traffic. Standard track in Britain comprises a
flat-bottom section of rail weighing 110 lb per yard (54 kg per metre)
carried on 2112 cross-sleepers per mile (1312 per km). Originally creosote-
impregnated wood sleepers [cross-ties] were used, but they are now made of
post-stressed concrete. This enables the rail to transmit the
pressure, perhaps as much as 20 tons/in2(3150 kg/cm2) fromthe small area of
contact with the wheel, to the ground below the track formation where it is
reduced through the sole plate and the sleeper to about 400 psi (28
kg/cm2). In soft ground, thick polyethylene sheets are generally placed
under the ballast to prevent pumping of slurry under the weight of trains.
    The rails are tilted towards one another on  1 in 20 sl. Steel
rails tnay last 15 or 20 years in traffic, but to prolong the undisturbed
life of track still longer, experiments have been carried out with paved
concrete track (PAC) laid by  slip paver similar to concrete highway
construction in reinforced concrete. The foundations, if new, are similar
to those for 
motorway. If on the other'hand, existing railway formation is to be used,
the old ballast is s1d with  bitumen emulsion before applying the
concrete which carries the track fastenings  glued in with cement grout or
epoxy resin. The track is made resilient by use of rubber-bonded cork
packings 0.4 inch (10 mm) thick. British Railways purchases rails in 60 ft
(18.3 m) lengths which are shop-welded into 600 ft (183 m) lengths and then
welded on site into continuous welded track with pressure-relief points at
intervals of several miles. The contfnuotls welded rails make for 
steadier and less noisy ride for the passenger and reduce the tractive
effort.



                    Signalling



    The second important factor contributing to safe rail  travel is the
system of signalling. Originally railways relied on the time interval to
ensure the safety of a succession of trains, but the defects rapidly
manifested themselves, and a space interval, or the block system, was
adopted, although it was not enforced legally on British passenger lines
until the
Regulation of Railways Act of 1889. Semaphore signals
became universally adopted on running lines and the interlocking  f points
[switches] and signals (usually accomplished mechanically by tappets) to
prevent conflicting movements being signalled was also  requirement of the
1889 t. Lock-and-block signalling, which ensured  safe sequence of
movements by electric checks, was introduced on the London, Chatham and
Dover Railway in 1875.
    Track circuiting, by which the presence of  train is detected by an
electric current passing from one rail to another through the wheels and
axles, dates from 1870 when William Robinson applied it in the United
States. In England the Great Eastern Railway introduced power operation of
points and signals at Spitaifields goods yard in 1899, and three years
later track-circuit operation of powered signals was in operation on 30
miles (48 km) of the London and Sout Western Railway main line.
    Day colour light signals, controlled automatically by the trains
through track circuits, were installed on the Liverpool Overhead Railway in
1920 and four-aspect day colour lights (red, yellow, double yellow and
green) were provided on Southern Railway routes from 1926 onwards. These
enable drivers of high-speed trains to have  warning two block sections
ahead of  possible need to stop. With track circuiting it became usual to
show the presence f vehicles on  track diagram in the signal cabin which
allowed routes to be controlled remotely by means of electric relays.
Today, panel
operation of considerable stretches of railway is common-l; at Rugby,
for instance,  signalman can control the points at  station 44 miles (71
km) away, and the signalbox at London Bridge controls movements on the
busiest 150 track-miles of British Rail. By the end of the I980s, the 1500
miles (241 km) of the Southern Region of British Rail are to be controlled
from 13 signalboxes. In modern panel installations the trains are not only
shown on the track diagram as they move from one section to another, but
the train identification number appears electronically in each section.
mputer-assisted train description, automatic train rporting and, at
stations such as London Bridge, operation of platform indicators, is now
usual.
    Whether points are operated manually or by an electric point motor,
they have to be prevented from moving while a train is passing over them
and facing points have to be locked, nd roved t  lkd (r 'detected'
) before th relevant signal can permit  train movement. The blades of the
points have to be closed accurately (.16 inch or 0.4 cm is the maximum
tolerance) so as to avert any possibility of  wheel flange splitting the
point and leading to  derailment.
    Other signalling developments of recent years include completely
automatic operation of simple point layouts, such as the double crossover
at the Bank terminus of the British Rails's Waterloo and City underground
railway. On London ransport's underground system  plastic roll operates
junctions according to the timetable by means of coded punched holes, and
on the Victoria Line trains are operated automatically once the driver has
pressed two buttons to indicate his readiness to start.  also acts as the
guard, controlling the opening f th doors, closed circuit television
giving him  view along the train. The trains are controlled (for
acceleration and braking) by coded impulses transmitted through the running
rails to induction coils mounted on the front of the train. The absence of
code impulses cuts off the current and applies the brakes; driving and
speed control is covered by command spots in which  frequency of 100 Hz
corresponds to one mile per hour (1.6 km/h), and l5 kHz
shuts off the current. Brake applications are so controlled that trains
stop smoothly and with great accuracy at the desired place on platforms.
Occupation of the track circuit ahead by  train automatically stops the
following train, which cannot receive  code.
    On ritish main lines an automatic warning system is being installed by
which the driver receives in his b  visual and audible warning of
passing  distant signal at caution; if he does not acknowledge the warning
the brakes are applied automatically. This is accomplished by magnetic
induction between  magnetic unit placed in the track and actuated
according to the signal aspect, and  unit on the train.



                    Train control



    In England train control began in l909 on the Midland Railway,
particularly to expedite the movement f coal trains and to see that guards
and enginemen were
relieved at the end of their shift and were not called upon to work
excessive overtime. Comprehensive train control systems, depending on
complete diagrams of the track layout and records of the position of
engines, crews and rolling stock, were developed for the whole of Britain,
the Southern Railway being the last to adopt it during World War 2, having
hitherto given  great deal of responsibility to signalmen for the
regulation of trains. Refinements f control include advance traffic
information(ATI) in which information is passed from yard to yard by telex
giving types of wagon, wagon number, route code, particulars f the load,
destination
station and consignee. In l972 British Rail decided to
adopt  computerized freight information and traffic control system known
as TOPS (total operations processing system) which was developed over eight
years by the Southern Pacific company in the USA.
    Although  great deal of rail 1rffi in Britain is handled by block
trains from point of origin to destination, about onefifth of the
originating tonnage is less than a train-load. This means that wagons must
be sorted on their journey. In Britain there are about 600 terminal points
on a 12,000 mile network whitch is served by over 2500 freight trains made
up of varying assortments of 249,000 wagons and 3972 locomotives, of witch
333 are electric. This requires the speed of calculation and the
information storage and classification capacity of the modern computer,
whitch has to be linked to points dealing with or generating traffic
troughout the system.The computer input, witch is by punched cards, covers
details of loading or unloading of wagons and their movements in trains,
the composition of trains and their departures from and arrivals at yards
,and the whereabouts of locomotives. The computer output includes
information on the balanse of locomotives at depots and yards, with
particulars  of when maintenanse examinations are due, the numbers  of
empty and loaded wagons, with aggregate weight and brake forse, and wheder
their movement is on time, the location of empty wagons and a forecast of
those that will become available, and the numbers of trains at any
location, with collective train weigts and individual details of the
component wagons.
    A closer check on what is happening troughoud the
system is thus provided, with the position of consignments in transit,
delays in movement, delays in unloading wagons by customers, and the
capasity of the system to handle future traffic among the information
readily available. The computer has a built-in self-check on wrong input
information.



                    Freight handling



    The merry-go-round system enables coal for power
stations to be loaded into hopper wagons at a colliery
without the train being stopped, and at the power station the train is
hauled round a loop at less than 2mph (3.2 km/h), a trigger devise
automatically unloading the wagons without the train being stopped. The
arrangements also provide for automatic weighing of the loads. Other bulk
loads can be dealt with in the same way.
    Bulk powders, including cement, can be loaded and discharged
pneumatically, using either ri1 wagons or containers. Iron ore is carried
in 100 ton gross wagons (72 tons of payload) whose coupling gear is
designed to swivel, so that wagons can be turned upside down for discharge
without uncoupling from their train. Special vans take palletized loads of
miscellaneous merchandise or such products as fertilizer, the van doors
being designed so that all parts of the interior can be reached by  fork-
lift truck.
    British railway companies began building their stocks of containers in
1927, and by 1950 they had the largest stock of large containers in Western
Europe. In 1962 British Rail decided to use International Standards
Organisation sizes, 8 ft (2,4 m) wide by 8 ft high and 1, 20, 30 and 40 ft
(3.1, 6.1, 9.2 and 12.2 m) long. The 'Freightliner' service of container
trains uses 62.5 ft (19.1 m) flat wagons with air-operated disc brakes in
sets f five and was inaugurated in 1965. At depots
'Drott' pneumatic-tyred cranes were at first provided but rail-mounted
Goliath cranes are now provided.
    Cars are handled by double-tier wagons. The British car industry is 
big user of 'omn' trains, which are operated for  single customer.
Both Ford and Chrysler use them to exchange parts between specialist
factories nd the railway thus becomes an extension of factory transport.
Company trains frequent1 consist of wagons owned by the trader; there are
about 20,000 on British railways, the oil industry, for example, providing
most f the tanks it needs to carry 21 million tons of petroleum products
by rail each year despite
competition from pipelines.
    Gravel dredged from the shallow seas is another developing source of
rail traffic. It is moved in 76 ton lots by 100 ton gross hopper wagons and
is either discharged on to belt conveyers to go into the storage bins at
the destination or, in another system, it is unloaded by truck-mounted
discharging machines.
    Cryogenic (very low temperature) products are also transported by rail
in high capacity insulated wagons. Such products include liquid oxygen and
liquid nitrogen which are taken from  central plant to strategically-
placed railheads where the liquefied gas is transferred to road tankers for
the journey to its ultimate destination.



                    Switchyards



    Groups of sorting sidings, in which wagons [freight cars] can be
arranged in order s that they can be
detached from the train at their destination with the least possible delay,
are called marshalling yards in Britain and classification yards or
switchyards in North America. The work is done by small locomotives called
switchers or shunters, which move 'cuts' of trains from one siding to
another until the desired order is achieved.
    As railways became more complicated in their system
layouts in the nineteenth century, the scope and volume of necessary
sorting became greater, and means of reducing the time and labour involved
were sought. ( 1930, for every 100 miles that freight trains were run in
Britain there were 75 miles of shunting.) The sorting of coal wagons for
return to the collieries had been assisted by gravity as early as 1859, in
the sidings at Tyne dock on the North Eastern Railway; in 1873 the London &
North Western Railway sorted traffic to and from Liverpool on the Edge Hill
'grid irons': groups of
sidings laid out on the slope of  hill where gravity provided the motive
power, the steepest gradient being 1 in 60 (one foot of elevation in sixty
feet of siding). Chain drags were used for braking he wagons.  shunter
uncoupled the wagons in 'cuts' for the various destinations and each cut
was turned into the appropriate siding. Some gravity yards relied on  code
of whistles to advise the signalman what 'road' (siding) was required.
    In the late nineteenth century the hump yard was introduced to provide
gravity where there was n natural slope of the land. In this the trains
were pushed up an artificial mound with  gradient of perhaps 1 in 80 and
the cuts were 'humped' down  somewhat steeper gradient on the other side.
The separate cuts would roll down the selected siding in the fan or
'balloon' of sidings, which would nd in  slight upward slope to assist in
the stopping of the wagons. The main means of stopping the wagons, however,
were railwaymen called shunters who had to run alongside the wagons and
apply the brakes at the right time. This was dangerous and required
excessive manpower.
    Such yards rd all over North America and north-east England and
began to be adopted elsewhere in England. Much ingenuity was devoted to
means of stopping the wagons;  German firm, Frohlich, came up with 
hydraulically  operated retarder which clasped the wheel of the wagon as it
went past, to slow it down to the amount the operator throught nssar.
    An entirely new concept came with Whitemoor yard at
March, near Cambridge, opened by the London & North
Eastern Railway in l929 to concentrate traffic to and from East Anglian
destinations. When trains arrived in one of ten reception sidings  shunter
examined the wagon labels and prepared  'cut card' showing how the train
should be sorted into sidings. This was sent to the control tower by
pneumatic tube; there the points [switches] for the forty sorted sidings
were preset in accordance with the cut card; information for several trains
could be stored in  simple pin and drum device.
    The hump was approached by  grade of 1 in 80. On the far side was 
short stretch of 1 in 18 to accelerate the wagons, followed by 70 yards {64
m) at 1 in 60 where the tracks divided into four, each equipped with 
Frohlich retarder. Then the four tracks spread out to four balloons of ten
tracks each, comprising 95 yards (87 m) of level track followed by 233
yards (213 m) falling at 1 in 200, with the remaining 380 yards
(348 m) level. The points were moved in the predetermined  sequence by
track circuits actuated by the wagons, but the operators had to estimate
the effects on wagon speed of the retarders, depending to  degree on
whether the retarders were grease or oil lubricated.
    Pushed by an 0-8-0 small-wheeled shunting engine at 1.5 to 2 mph (2.5
to 3 km/h),  train of 70 wagons could be sorted in seven minutes. The yard
had  throughput of about 4000 wagons  day. The sorting sidings were
allocated: number one for Bury St Edmunds, two for Ipswich, and s forth.
Number 31 was for wagons with tyre fastenings which might be ripped off by
retarders, which were not used on that siding. Sidings 32 t 40 were for
traffic to be dropped at wayside stations; for these sidings there was an
additional hump for sorting these wagons in station order. Apart from the
sorting
sidings, there were an engine road,  brake van road, 
'cripple' road for wagons needing repair, and transfer road to three
sidings serving  tranship shed, where small shipments not filling entire
wagons could be sorted.
    British Rail built  series of yards at strategic points; the yards
usually had two stages of retarders, latterly electropneumatically
operated, to control wagon speed. In lateryards electronic equipment was
used to measure the weight of each wagon and estimate its
rolling resistance. By feeding this information into  computer,  suitable
speed for the wagon could be determined and the retarder
operatedautomatically to give the desired amount of braking. These
predictions did not always prove reliable.
    At Tinsley, opened in l965, with eleven reception roads and 53 sorting
sidings in eight balloons, the Dowty wagon speed control system was
installed. The Dowty system uses many small units (20,000 at Tinsley)
comprising hydraulic rams on the inside of the rail, less than  wagon
length apart. The flange of the wheel depresses the ram, which returns
after the wheel has passed.  speed-sensing device determines whether the
wagon is moving too fast from thehump; if the speed is too fast the ram
automatically has  retarding action.
Certain of the units are booster-retarders; if the wagon is moving too
slowly,  hydraulic supply enablesthe ram to accelerate the wagon. There
are 25 secondary sorting
sidings at Tinsley to which wagons are sent over 
secondary hump by the booster-retarders. If individual unitsfail the rams
can be replaced.
    An automatic telephone exchange links ll the traffic and
administrative offices in the yard with the railway controlffi,
Sheffield Midland Station and the local steelworks(principal source of
traffic). Two-w loudspeaker systems are available through all the
principal points in the yard, and radio telephone equipment is used t
speak to enginemen. Fitters maintaining the retarders have walki-talkie
equipment.
The information from shunters about the cuts and how many wagons in each,
together with destination, is
conveyed by special data transmission equipment,  punched tape being
produced to feed into the point control system for each train over the
hump.
    As British Railways have departed from the wagon-load system there is
less employment for marshalling yards. Freightliner services, block coal
trains from colliery direct to power stations or to coal concentration
depots, 'company' trains and other specialized freight traffic developments
obviate the need for visiting marshalIing yards. Other  factors are
competition from motor transport, closing of wayside freight depots and of
many small coal yards.



                    Modern passenger service



    In Britain  network of city tocity services operates at speeds of up
to 100 mph (161 km/h) and at regular hourly intervals, or 30 minute
intervals on such routes as London to Birmingham. On some lines the speed
is soon to be raised to 125 mph (201 km/h)with high speed diesel trains
whos prototype has been shown to be
capable of 143 mph (230 km h). With the advanced passenger train (APT) now
under development, speeds of 150 mph (241 km/h) are envisaged. The Italians
are developing  system capable of speeds approaching 200 mph (320 km/h)
while the Japanese and the French already operate passenger trains at
speeds of about 150mph (241 km/h).
    The APT will be powered either by electric motors or by gas turbines,
and it can use existing track because of its pendulum suspension which
enables it to heel over when travelling round curves. With stock hauled by
 conventional locomotive, the London to Glasgow electric service holds the
European record for frequency speed over  long distance. When the APT is
in service, it is expected that the London to Glasgow journey time of five
hours will be reduced to 2.5 hours.
    In Europe  number of combined activities organized
through the International Union af Railways included the
Trans-Europe-Express (TEE) network of high-speed passenger trains, 
similar freight service, and  network of railway-ssociated road services
marketed as Europabus.



                    Mountain railways



    Cable transport has always been associated with hills and mountains. In
the late 1700s and early 1800s the wagonways used for moving coal from
mines to river or sea ports were hauled by cable up and down inclined
tracks. Stationary steam engines built near the top of the incline drove
the cables, which were passed around  drum connected to the steam engine
and were carried on rollers along the track. Sometimes cable-worked
wagonways were self-acting if loaded wagons worked downhill, fr they could
pull up the lighter empty wagons. Even after George Stephenson perfected
the travelling steam locomotive to work the early passenger railways of the
1820s and 1830s cable haulage was sometimes used to help trains climb the
steeper gradients, and cable working continued to be used for many steeply-
graded industrial wagonways throughout the 1800s. Today  few cable-worked
inclines survive at industrial sites and for such unique forms of transport
as the San Francisco tramway [streetcar] system.



                    Funiculars



    The first true mountain railways using steam
locomotives running on  railway track equipped for rack and pinion
(cogwheel) propulsion were built up Mount Washington, USA, in 1869 and
Mount Rigi, Switzerland, in 1871. The latter was the pioneer of what today
has become the most extensive mountain transport system in the world. Much
of Switzerland consists of high mountains, some exceeding l4,000 ft (4250
m). From this development in mountain transport other methods were
developed and in the following 20 years until the turn of the century
funicular railways were built up  number of mountain slopes. Most worked
on  similar principle to the cliff lift, with two cars connected by cable
balancing each other. Because of the length of some
lines, one mile (1.6 km) or more in  few cases, usually only  single
track is provided over most of the route, but a short length of double
track is laid down at the halfway point where the cars cross each other.
The switching of cars through the double-track section is achieved
automatically by using double-flanged wheels on one side of each ar and
flangeless wheels on the other so that one car is always guided through the
righthand track and the other through the left-hand track. Small gaps are
left in the switch rails to allow the cable t pass through without
impeding the wheels.
    Funiculars vary in steepness according to location and may have gentle
curves; some are not steeper than 1 in 10 (10per cent), others reach 
maximum steepness of 88 per cent.On the less steep lines the cars are
little different from, but smaller than, ordinary railway carriages. On the
steeper lines the cars have  number of separate compartments, stepped up
one from another so that while floors and seats are level a compartment at
the higher end may be I0 or even 15 ft (3 or 4 m) higher than the lowest
compartment at the other end. Some of the bigger cars seat 100 passengers,
but most carry
fewer than this.
    Braking and safety are of vital importance on steep mountain lines to
prevent breakaways. Cables are regularly inspected and renewed as necessary
but just in case the cable breaks a number of braking systems are provided
to stop the car quickly. On the steepest lines ordinary wheel brakes would
not have any effect and powerful spring-loaded grippers on the r
underframe act on the rails as soon as the cable becomes slack. When 
cable is due for renewal the opportunity  is taken to test the braking
system by cutting the cable
nd checking whether the cars stop within the prescribed
distance. This operation is done without passengers
    The capacity of funicular railways is limited to the two cars, which
normally do not travel at mr than about 5 to 1 mph (8 to 16 km/h). Some
lines are divided 1nt sections with pairs f cars covering shorter
lengths.



                    Rack railways



    The rack and pinion system principle dates
from the pioneering days of the steam locomotive between
1812 and 1820 which coincided with the introduction of
iron rails. 0ne engineer, Blenkinsop, did not think that
iron wheels on locomotives would have sufficient grip on
iron rails, and on the wagonway serving Middleton colliery near Leeds he
laid an extra toothed rail alongside one of the ordinary rails, which
engaged with  cogwheel on the locomotive. The Middleton line was
relatively level and it was soon found that on railways with only gentle
climbs the rack system was not needed. If there was enough weight on the
locomotive driving wheels they would grip the rails by friction. Little
more was heard of rack railways until the 1860s, when they began to be
developed for mountain railways in the USA and Switzerland.
    The rack system for the last 100 years has used an additional centre
toothed rail which meshes with cogwheels under locomotives and coaches.
There are four basic types of rack varying in details: the Riggenbach type
looks like  steel ladder, and the Abt and Strub types use  vertical rail
with teeth machined out of the top. 0ne or other of these systems is used
on most rack lines but they are safe only on gradients n steeper than 1 in
4 (25 per cent). One line in Switzerland up Mount Pilatus has  gradient of
1 in 2 (48 per cent) and uses the Locher rack with teeth cut on both sides
of the rack rail instead of on top, engaging with pairs of
horizontally-mounted cogwheels on each side, drivihg and
braking the railcars.
    The first steam locomotives for steep mountain lines had vertical
boilers but later locomotives had boilers mounted at an angle to the main
frame so that they were virtually horizontal when on the climb. Today steam
locomotives have all but disappeared from most mountain lines nd survive
in regular service on only one line in Switzerland, on Britain's only rack
line up Snowdon in North Wales, and  handful of others. Most of the
remainder have been electrified or  few converted to diesel.



                    Trams and trolleybuses



    The early railways used in mines with four-wheel trucks and wooden
beams for rails were known as tramways. From this came the word tram for 
four-wheel rail vehicle. The world's first street ri1w, or tramway, was
built in New York in 1832; it was  mile (1,6 km) long and known as the New
York & Harlem Railroad. There were two horse-drawn rs, each holding 30
people. The one mile route had grown to four miles (6.4 km) by 1834, and
cars were running every 15 minutes; the tramway idea spread quickly and in
the 1880s there were more than 18,000 horse trams in the USA and over 3000
miles (4830 km) of track. The building f tramways, or streetcar systems,
required the letting of construction contracts and the acquisition of right-
of-way easemerits, and was an area of political patronage and corruption in
many cit governments.
    The advantage of the horse tram over the horse bus was that steel
wheels on steel rails gave  smoother ride and less friction.  horse could
haul on rails twice as much weight s on  roadway. Furthermore, the trams
had brakes, but buses still relied on the weight of the horses to stop the
vehicle. The American example was followed in Europe and the first tramway
in Paris was opened in 1853 appropriately styled 'the American Railway'.
The first line in Britain was opened in Birkenhead in 1860. It was built by
George Francis
Train, an American, who also built three short tramways in London in 1861:
the first f these rn from rbl Arch for  short distance along the
Bayswater Road. The lines used  type of step rail which stood up from the
road surface and interfered with other traffic, so they were taken up
within  year. London's more permanent tramways began running in 1870, but
Liverpool had  1in working in November 1869. Rails which could be laid
flush with the road surface were used for these lines.
     steam tram was tried out in Cincinatti, Ohio in 1859 and in London in
1873; the steam tram was not widely successful because tracks built for
horse trams could not stand up t th weight of  locomotive.
    The solution to this problem was found in the cable r. Cables, driven
by powerful stationary steam engines at the end of the route, were run in
conduits below the roadway, with an attachment passing down from the tram
through  slot in the roadway to grip the cable, and the car itself weighed
n more than  horse car. The most famous application of cables to tramcar
haulage was Andrew S Hallidie's  1873 system on the hills of San Francisco
 still in use and  great tourist attraction today. This was followed by
others in United States cities, and by 1890 there were some 500 miles (805
km) of cable tramway in the USA. In London there were only two cable-
operated lines  up Highgate Hill from 1884 (the first in Europe) and up
the hill between Streatham and Kennington. In Edinburgh, however, there was
an extensive cable system, as there was in Melbourne.
    The ideal source of power for tramways was electricity, clean and
flexible but difficult at first to apply. Batteries were far too heavy; 
converted horse r with batteries under the seats and  single electric
motor was tried in London in 1883, but the experiment lasted only one day.
Compressed air driven trams, the invention of jr Beaumont, had been
tried out between Stratford and Leytonstone in 1881; between 1883 and 1888
tramcars hauled by battery locomotives  ran on the same route. There was
even  coal-gas driven tram  with an Otto-type gas engine tried in Croydon
in 1894.
    There were early experiments, especially in the USA and Germany, to
enable electricity from  power station to be fed to  tramcar in motion.
The first useful system emp1d  small two-wheel carriage running on top
of an overhead wire and connected t the tramcar by  cable. The circuit
was completed  via wheels and the running rails.  tram route on this
system  was working in Montgomery, Alabama, as early as 1886. The cohverted
horse cars had  motor mounted on one of the end platforms with chain drive
to one axle. Shortly afterwards, in the USA and Germany there wer trials
on  similar principle but using  four-wheel overhead carriage known as 
troller, from which the modern word trolley is derived.
    Real surcess came when Frank J Sprague left the US Navy in 1883 to
devote more time to problems of using electricity for power. His first
important task was to equip the Union Passenger Railway at Richmond,
Virginia, for lectrical working. There he perfected the swivel trolley
1 which could run under the overhead wire instead of above it. From this
success in 1888 sprang all the subsequent tramways of the world; by 1902
there were nearly 22,000 miles (35,000 km) of
ltrified tramways in the USA alone. In Great Britain there were electric
trams in Manchester from 1890 and London's first electric line was opened
in 1901.
    Except in Great Britain and countries under British
influence, tramcars were normally single-decked. Early
electric trams had four wheels and the two axles were quite close together
so that the car could take sharp bends. Eventually, as the need grew for
larger cars, two bogies, or trucks, were used, one under each end of the
car. Single-deck cars of this type were often coupled together with 
single driver and one or two conductors, Double-deck cars could haul
trailers in peak hours and for  time such trailers were  common sight in
London.
    The two main power collection systems were from
overhead wires, as already described  though modern
tramways often use  pantograph collecting devi held by springs against
the underside of the wire instead of the traditional trolley  and the
conduit system. This system is derived from the slot in the street used for
the early cablecars, but instead of  moving cable there are current supply
rails in the conduit. The tram is fitted with  device called  plough
which passes down into the conduit. On each side of the plough is  contact
shoe, one of which presses against each of the rails. Such  system was
used in inner London, in New York and Washington DC, and in European
cities.
    Trams were driven through  controller on each platform. In  single-
motor car, this allowed power to pass through  resistariceas well as the
motor, the amount f resistanc being reduced in steps by moving  handle
as desired, to feed more power to the motor. In two-motor cars  much more
economical  ntrol was used. When starting, the two motors were nnctd
in series, so that each motor received power in turn  in effect, each got
half th power available, the amount of power again being regulated b
resistances. As speed rose
the controller was 'notched up' to  further set of steps in which the
motors were connected in parallel so that each reived current direct from
the power source instead o sharing it. The ntrllr could also be moved
to  further set of notches which gave degrees of 1trical braking,
achieved by connecting the motors so that they acted as generators, the
power generated being absorbed by the resistances. n merican tramcar
revival in the I930s resulted in the design of  new tramcar known as the
 type after the Electric Railway Presidents nfrnce Committee which
commissioned it. These cars, of which many hundreds were built, had more
refined controllers with more steps, giving smoother acceleration.
    The decline of the tram springs from the fact that while  tram route
is fixed,  bus route can be changed as the need for it changes. The
inability of  tram to draw in to the kerb to discharge and take on
passengers was  handicap when road traffic increased. The tram has
continued to hold its own in some cities, especially, in Europe; its
character, however, is changing and tramways are becoming light rapid
transit railways, often diving underground in the centres of cities. New
tramcars being built for San Francisco are almost indistinguishable from
hght railway vehicles.
    The lack of flexibility of the tram led to experiments to dispense with
rails altogether and to the trolleybus, r trackless tram. The first crude
versions were tried out in Germany and the USA in the early 1880s. The
current llection system needed two cables and collector arms, sine there
were n rails.  short line was tried just outside Paris in 1900 and an
even shorter one  800 feet (240 m)  opened in Scranton, Pennsylvania, in
l903. In England, trolleybuses were operating in Bradford and Leeds in 1911
and other cities
soon followed their example. America and Canada widely
changed to trolleybuses in the early l920s and many cities had them. The
trolleybuses tended to look, except for their mllector arms, like
contemporary motor buses. Londons first trolleybus, introduced in 1931,
was based on  six-wheel bus chassis with an electric motor substituted for
the engine. The London trolleybus fleet, which in 1952 numbered over 1800,
was for some years the largest in the world, and was composed almost
entirely of six-wheel double-deck vehicles.
    The typical trolleybus was operated by means of  pedal-operated master
control, spring-loaded to the 'off' position, and a reversing lever. Some
braking was provided by the electric motor controls, but mechanical brakes
were relied upon for safety. The same lack of flexibility which had
ndemned trams in most parts f the world also condemned thetrolIeybus.
They were tied as firmly to the overhead wires as were the trams
to the rails.



                    Monorail systems



    Monorails are railways with only one rail instead f two. They have
been experimentally built for more than  hundred years; there would seem
to be an advantage in that one rail and its sleepers [cross-ties] would
occupy less space than two, but in practice monorail construction tended to
be complicated on account of the necessity of keeping the cars upright.
There is also the problem of switching the cars from one line to another.
    The first monorails used an elevated rail with the cars hanging down on
both sides, like pannier bags [saddle bags] on  pony or  bicycle. 
monorail was patented in 1821 by Henry Robinson Palmer, engineer to the
London Dock Company, and the first line was built in 1824 to run between
the Royal Victualling Yard and the Thames. The elevated wooden rail was 
plank on edge bridging strong wooden supports, into which it was set, with
an iron bar on top to take the wear from the double-flanged wheels of the
cars.  similar line was built to carry bricks to River Lea barges from 
brickworks at Cheshunt in 1825. The cars, pulled by  horse and  tow r,
were in two parts, one on each side of the rail, hanging from a framework
which carried the wheels.
    Later, monorails on this principle were built by  Frenchman,  F M T
Lartigue.  put his single rail on top of  series of triangular trestles
with their bases on the ground; he also put  guide rail on each side of
the trestles on which ran horizontal wheels attached to the cars. The cars
thus had both vertical and sideways support nd were suitable for higher
speeds than the earlier type.
     steam-operated line on this principle was built in Syria in 1869 by J
L Hadden. The locomotive had two vertical boilers, n on each side f the
pannier-type vehicle.
    An electric Lartigue line was opened in central France in 1894, and
there were proposals to build  network of them on Long Island in the USA,
radiating from Brooklyn. There was  demonstration in London in 1886 on 
short line, trains  being hauled by  two-boiler Mallet steam locomotive.
This had two double-flanged driving wheels running on the raised centre
rail and guiding wheels running on tracks on each side of the trestle.
Trains were switched from one track to anothe
by moving  whole section of track sideways to line up with another
section. In 1888  line on this principle was laid in Ireland from Listowel
to llybunion,  distance of 9,5 miles; it ran until 1924. There were
three locomotives, each with two horizontal boilers hanging one each side
of the centre wheels. They were capable of 27 mph (43.5 km/h); the
carriages wr built with the lower parts in two sections, between which
were the wheels.
    The Lartigue design was adapted further by F B Behr, who built  three-
mil electric line near Brussels in l897. The mnri1 itself was again at
the top of n '' shaped trestle, but there were two balancing and guiding
rails on each side, s that although the weight of the r was carried by
one rail, ther were really five rails in ll. The r weighed 55 tons and
had two four-wheeled bogies (that is, four wheels in line n each bogie).
It was built in England and had motors putting
out  total of 600 horsepower. The r ran at 83 mph (134 km/h) and was
said to have reached 100 mph (161 km/h) in private trials. It was
extensively tested by representatives of the Belgian, French and Russian
governments, and Behr came near to success in achieving wide-scale
application of his design.
    An attempt to build  monorail with one rail laid on the ground in
order to save space led to the use of  gyroscope to keep the train
upright.  gyroscope is  rapidly spinning flywheel which resists any
attempt to alter the angle of the axis on which it spins.
     true monorail, running on  single rail, was built for military
purposes by Louis Brennan, an Irishman who also invented  steerable
torpedo. Brennan applied for monorail patents in 1903, exhibited  large
working model in 1907 and  full-size 22-ton car in 1909  10. It was held
upright by two gyroscopes, spinning in opposite directions, and carried 50
people or ten tons of freight.
     similar r carrying only six passengers and  driver was
demonstrated in Berlin in 1909 by August Scherl, who had taken out  patent
in 1908 and later m to an agreement with Brennan to use his patents
also. Both systems allowed the cars to lean over, like bicycles, on curves.
Scherl's was an electric car; Brennan's was powered by an internal
combustion  engine rather than steam so as not to show any tell-tale smoke
when used by the military.  steam-driven gyroscopic system was designed by
Peter Schilovsky,  Russian nobleman. This reached only the model stage; it
was held upright by  single steam-driven gyroscope placed in the tender.
    The disadvantage with gyroscopic monorail systems was that they
required power to drive the gyroscope to keep the train upright even when
it was not moving.
    Systems were built which ran on single rails on the ground but used 
guide rail at the top to keep the train upright. Wheels on top of the train
engaged with the guiding rail. The structural support necessary for the
guide rail immediately nullified the economy in land use which was the main
argument in favour of monorails.
    The best known such system was designed by   Tunis
and built by August Belmont. It was 1,2 miles long (2.4 km) and ran between
Barton Station on the New York, New
Haven & Hartford Railroad and City Island (Marshall's
Corner) in 1,2 minutes. The overhead guide rail was arranged to make the
single car lean over on  curve and the line was designed for high speeds.
It ran for four months in l9I0, but on 17 July f that year the driver took
 curve too slowly, the guidance system failed and the car crashed with 100
people on board. It never ran again.
    The most successful modern monorails have been the
invention of Dr Axel L Wenner-Gren, an industrialist born in Sweden. Alweg
lines use  concrete beam carried on concrete supports; the beam can be
high in the air, at ground level or in  tunnel, as required. The cars
straddle the beam, supported by rubber-tyred wheels on top f the beam;
there are also horizontal wheels in two rows on each side underneath,
bearing on the sides of the beam near the top and bottom of it. Thus there
are five bearing surfaces, as in the Behr system, but combined to use 
single beam instead of  massive steel trestle framework. The carrying
wheels m up into the centre line of the cars, suitably enclosed.
Electric current is picked up from power lines at the side
of the beam.  number of successful lines have been built on the Alweg
system, including  line 8.25 miles (13.3 km) long between Tokyo and its
Haneda airport.
    There are several other 'saddle' type systems on the same principle as
the Alweg, including  small industrial system used on building sites and
for agricultural purposes which can run without  driver. With all these
systems, trains are diverted from one track to another by moving pieces of
track sideways to bring in another piece of track to form  new link, or by
using  flexible section of track to give the same result.



                    Other systems



    Another monorail system suspends the car beneath an overhead carrying
rail. The wheels must be over the centre line of the car, so the support
connected between
ri1 and car is to one side, or offset. This allows the rail to be
supported from the other side. Such  system was built between the towns of
Barmen and Elberfeld in Germany in 1898-1901 and was extended in 1903 to 
length of 8.2 miles (13 km). It has run successfully ever since, with 
remarkable safety record. Tests in the river valley between the towns
showed that  monorail would be more suitable than  conventional railway
in the restricted space available because monorail cars could take sharper
curves in comfort.
The rail is suspended on  steel structure, mostly over the River Wupper
itself. The switches or points on the line are in the form of  switch
tongue forming an inclined plane, which is placed over the rail; the car
wheels rise on this plane and are thus led to the siding.
    An experimental line using the same principle of suspension, but with
the r driven by means f an aircraft propeller, was designed by George
Bennie and built at Milngavie (Scotland) in 1930. The line was too short
for high speeds, but it was claimed that 200 mph (322 km/h) was possible.
There was an auxiliary rail below the car on which horizontal wheels ran to
control the sway.
     modern system, the SAFEGE developed in France, has
suspended cars but with the 'rail' in the form of  steel box section split
on the underside to allow the car supports to pass through it. There are
two rails inside the b, one on each side of the slot, and the cars are
actually suspended from four-wheeled bogies running on the two rails.



                    Underground railways



    The first underground railways were those used in mines, with small
trucks pushed by hand or, later, drawn by ponies, running on first wooden,
then iron, and finally steel rails. Once the steam railway had arrived,
howevr, thoughts soon turned to building passenger railways under the
ground in cities to avoid the traffic congestion which was already making
itself felt in the streets towards the middle of the 19th century.
    The first underground passenger railway was opened in London on 1
January, 1863. This was the Metropolitan Railway, 3.75 miles (6 km) long,
which ran from Paddington to Farringdon Street. Its broad gauge (7 ft, 2.13
m) trains, supplied by the Great Western Railway, were soon carrying nearly
27,000 passengers  day. Other underground lines followed in London, and in
Budapest, Berlin, Glasgow, Paris and later in the rest of Europe, North and
South America, Russia, Japan, China, Spain, Portugal and Scandinavia, and
lans and studies for yet more underground railways have already been
turned into reality  r soon will be  all over the world. Quite soon
every major city able to d so will have its underground railway. The
reason is the same as that
which inspired the Metropolitan Railway over 100 years ago traffic
congestion.
    The first electric tube railway [subway] in the world,the City and
South London, was opened in 1890 and all subsequent tube railways have been
electrically worked. Subsurface cut-and-cover lines everywhere are also
electrically worked. Th early locomotives used on undergroundrailways have
given way to multiple-unit trains, with separate motors at various points
along the train driving the wheels, but controlled from  single driving
b.
    Modern underground railway rolling stock usually has
plenty of standing space to cater for peak-hour crowds and alarge number of
doors, usually opened and closed by the driver or guard, so that passengers
can enter and leave the trains quickly at the many, closely spaced
stations. Average underground railway speeds are not high  often between
20 and 25 mph (32 to 60km/h) including stops, but the trains are usually
much quicker than surface transport in the same area. Where underground
trains emerge into the open on the dge
of cities, and stations are  greater distance apart, they can often attain
well over 60 mph (97 km/h).
    The track and ltricit supply are usually much the same as that of
main-line railways and most underground lines use forms f automatic
signalling worked by the trains themselves and similar to that used by
orthodox railway systems. The track curcuit is the basic component of
automatic signalling of this type on ll kinds of railways. Underground
railways rely heavily on automatic signalling because of the close
headways, the short time intervals between trains.
    Some railways have n signals in sight, but the signal 'aspects' 
green, yellow and red  are displayed to the driver in the  of his
train. Great advances are being made also with automatic driving, now in
use in  number of cities. he Victoria Line system in London, the most
fully automatic line now in operation, uses codes in the rails for both
safety signalling and automatic driving, the codes being picked up by coils
on the train and passed to the driving and monitoring equipment.
    Code systems are used on other underground railways but sometimes they
feed information to  central computer, which calculates where the train
should be at any given time, nd instructs the train to slow down, speed
up, stop, or take any other action needed.