A ROBOT TRAIN

Evening Post, Volume CXXV, Issue 22, 27 January 1938, Page 23

A ROBOT TRAIN

RUNS UNDER LONDON

POST OFFICE RAILWAY

No other system of transport can be compared with Britain's robot railway which conveys letters and parcels six and a half miles' between Paddington Station and Whitechapel (writes Ellis Fanshawe'in the "Adelaide Chronicle"). Its very existence is not widely known, and compara-tively-few Londoners ate aware that beneath their feet trains may be running at a speed of'3s miles an hour without -human control of any kind. The London Post Office Railway is a unique system of transport in that the trains are operated without drivers. When a train is" about 100 yards from the platform, human control. over it ceases, and is not exercised again until the train comes within the same distance of the next station. The construction of this railway, which was opened for service in December, 1927, cost £1,750,000, and it is the only one in the world operated by a system of remote control..

There are eight stations, ranging from 60 to 90 feet below the road surface, and these are situated at Whltechapel (near the London Hospital), Liverpool Street' Station, St. ! Martin's le Grand (King Edward Building)1, Mount Pleasant, High Hojborn, Wimpole Street, Bird Street, and Paddington Station. Each station is bejrieath a post office building, with the exception of Liverpool Street, where th"c station is below the main line railway. The stations are equipped with lifts and spiral chutes, and.in some cases with conveyors and bagelevators. Platforms vary, in lengthfrom 90 feet at Bird Street to 313. feet, at. Mount Pleasant: .',■■.

In appearance the stations are much the same, as those of passenger tube railway stations, but the railway itself; of course, is in miniature. The lines of' two-feet gauge double track arej laid in a tunnel nine feet in diameter i —except in station approaches, where the tracks are separated into two seven-foot tunnels. At the, stations there are two sets of tracks each way; one track for "through" trains and the other for "stopping" trains. One or more berths for trains are provided at eaph platform. LENGTH OF TRAINS. The trains may consist of one or two cars, which are of the "bogie" type with an over-all length of 27ft. The cars are in reality of framework designed for carrying four mail-bag containers, and these; containers are moved at will on to the platforms.

.The method of control may be better understood when it is-explained that the normal position of the train's brakes is "on." Brakes are released only when the particular section of track in which the train stands is energised. :Not until the motors receive current are the brakes released to start the train. • Thus every train is brought to a standstill \vhen itenters a "dead" section, for when the current is cut off the brakes apply themselves automatically. Human conirol is exercised when the train is approaching a station, w.hile it is in the station, and when it leaves the station. After the train has passed out of the station section, it gradually gathers speed and thereafter its .progress is automatic,

Inside the station section the control is entirely in the hands of a switchman, who sits in a compartment on the station platform that is not Unlike a signal cabin. When the plat-

form stall have loaded a irain a signal Is given to the switchman, who moves a switch that energises the section on which the train is standing—thus releasing the brakes and setting the train in motion. As the train nears the next station, it enters what is called a braking section, which is a short dead section on an upgrade of one in twenty, and it reduces the speed of the train so that it comes to rest gradually on the station section. Every train must come to a standstill just outside a station unless it happens to be a "through" train. If the switchman can receive the train he operates one oC his "receive" levers, and this not only sets the necessary point, but also starts a camshaft motor. Now the camshaft motor closes three contactors progressively, and brings the train into the station berth on three different voltages. THE DEAD/ SECTION. When a train is running free in the tunnels the main voltage'is 440, which is reduced by the second camshaft contactor to 260 volts. The third camshaft contactor reduces the voltage to obtain a speed of eight miles an hour for entering the station. A station berth is a dead section, so that there the brakes immediately resume the normal, or "on" position. These brakes are operated by powerful springs, which can only be pulled off by elec-tro-magnets, when the current is applied to the dead section. As the trains stop the platform staff release the mailbag containers and drag them on to the platform. Every effort is made to save labour and to reduce the man-handling of mailbags to a!minimum. Each-of the containers has.a collapsible, bottom and they are either wheeled into the lifts or—at those stations where under-platform conveyors are installed—over apertures in the platform. The porter operates a lever of the mailbag container, and the bottom opens so that mailbags are shot on to conveyors feeding into bucket elevators which take them up to the offices above the stations. Mailbags descend from the offices to the station platform by means of spiral chutes, and their destination can be. ascertained by the platform staff at a glance. * Each mailbag has a coloured label, and there is a. special colour for each particular station, so that the destination is known, immediately a bag appears on the platform. When a train enters a station berth, the staff knows the destination of mailbags within the containers before opening them. At Paddington the under-platform conveyors connect with' other conveyors which take the bags on to that part of the Great Western -Railway platform known as the "lawn." For dealing conveniently with large consignments of mails'from the. provinces and abroad several apertures have been provided in the arrival platforms at Paddington arid Liverpool Street main line stations. These apertures give access to chutes and conveyors which, feed on to the.post office rail- ■ way platform; ,