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 rаi1 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 а 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 1О, 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 оf 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 а

big user of 'сomраnу' trains, which are operated for а single customer.

Both Ford and Chrysler use them to exchange parts between specialist

factories аnd the railway thus becomes an extension of factory transport.

Company trains frequent1у consist of wagons owned by the trader; there are

about 20,000 on British railways, the oil industry, for example, providing

most оf 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 а 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 sо 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. (Ву 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 а 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. А shunter

uncoupled the wagons in 'cuts' for the various destinations and each cut

was turned into the appropriate siding. Some gravity yards relied on а 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 nо natural slope of the land. In this the trains

were pushed up an artificial mound with а gradient of perhaps 1 in 80 and

the cuts were 'humped' down а 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 еnd in а 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 арреаrеd 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; а German firm, Frohlich, came up with а

hydraulically operated retarder which clasped the wheel of the wagon as it

went past, to slow it down to the amount the operator throught nесеssarу.

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 а shunter

examined the wagon labels and prepared а '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 а simple pin and drum device.

The hump was approached by а grade of 1 in 80. On the far side was а

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 а

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 а 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), а train of 70 wagons could be sorted in seven minutes. The yard

had а throughput of about 4000 wagons а day. The sorting sidings were

allocated: number one for Bury St Edmunds, two for Ipswich, and sо 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 tо 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, а brake van road, а

'cripple' road for wagons needing repair, and transfer road to three

sidings serving а tranship shed, where small shipments not filling entire

wagons could be sorted.

British Rail built а 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 а computer, а 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 а wagon

length apart. The flange of the wheel depresses the ram, which returns

after the wheel has passed. А speed-sensing device determines whether the

wagon is moving too fast from thehump; if the speed is too fast the ram

automatically has а retarding action.

Certain of the units are booster-retarders; if the wagon is moving too

slowly, а hydraulic supply enablesthe ram to accelerate the wagon. There

are 25 secondary sorting

sidings at Tinsley to which wagons are sent over а

secondary hump by the booster-retarders. If individual unitsfail the rams

can be replaced.

An automatic telephone exchange links аll the traffic and

administrative offices in the yard with the railway controlоffiсе,

Sheffield Midland Station and the local steelworks(principal source of

traffic). Two-wау loudspeaker systems are available through all the

principal points in the yard, and radio telephone equipment is used tо

speak to enginemen. Fitters maintaining the retarders have walkiе-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, а 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 а 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

whosе 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 а 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

а conventional locomotive, the London to Glasgow electric service holds the

European record for frequency speed over а 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 а number of combined activities organized

through the International Union af Railways included the

Trans-Europe-Express (TEE) network of high-speed passenger trains, а

similar freight service, and а network of railway-аssociated 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 а 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, fоr 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 а 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 а 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 а number of mountain slopes. Most worked

on а 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 а few cases, usually only а 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 сar 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 tо 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 а

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 а 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 саr

underframe act on the rails as soon as the cable becomes slack. When а

cable is due for renewal the opportunity is taken to test the braking

system by cutting the cable

аnd 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 mоrе than about 5 to 1О mph (8 to 16 km/h). Some

lines are divided 1ntо sections with pairs оf 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 а 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 а steel ladder, and the Abt and Strub types use а vertical rail

Страницы: 1, 2, 3, 4