HOW RAILWAYS TALK.

Otago Witness, Issue 2387, 30 November 1899, Page 62

HOW RAILWAYS TALK.

CHATS IN RED AND GEEEN. .

Have you ever been in a busy signal-box by night, the windows of which command a over, perhaps, two or three acres sqvare of railway^tines, with a vast number ot mutable lights?- varying in hues of red, white, and green? It is a charming sight. But one which I must ask the reader not to entertain any sanguine hopes of witnessing from tins point, as all signal-boxes are necessarily kept strictly private, in order ndt to divert the attention or confuse the mind of the signalman. From here locomotives and vehicles can b u , seen moving about in all directions in various parts of the yard. Now a passenger train, guided by the symbolical lights along the line, is-' rushing through at bho rate of 40 or 50 miles an hour. Its course through the yard is quickly filled by a gcods train from the adjoining line. Now an express is hurrying through in the opposite direction, leaving in its trail a long column of smoke and steam. The goods recrosses, and in a few minutes more is following in the wake of the express. The exterior workings, as seen from the signal-box windows, tend to confuse rather than enlighten the onlooker, and lniglil" reasonably cause him to wonder how these are effected with such marvellous facility and a minimum of accidents. To know this, a description of the signalbox, with its working, is necessary, for it "is here the secrets lie, and' herein fhe run- • ning of the trains is regulated. The first object in the box that meets thfc eye is a long row of, perhaps, 50 <t O'J levers, the top pp-rts of which are brightly polished, while the bottom parts (about two-thirds) are painted in various colours, indicative to what they apply. For instance, black denotes that ;iJ levers painted in this colour work the SAvitciies which turn tlu- engines from one line to another ; red, danger signils; blue, safety locking-bars; and so on. In addition to this, there is a biass plate, on which the use of the lever is inscribed, and another, upon which is inscribed the consecutive number of the lever, attached to each Je^er. There" is also a diagram of all the switches and points and signals, with instructions for working, hung up in a compicuous position in the box. But how is it lhat the signalman, who is ctiitinually pushing and pulling the levers, nowr puii* the wrong one, thereb}' throwing the train off the line, or turning it out of its course? This is a question often asked, most people being under the '■nnression that all ' the levers can be pulled at any time and anyhow. Happily this is a fallacy which may be got rid of by a brief explanation of a kind of mechanism known a.s interlocking. Tins interlocking gear is generally in the bottom stoiey of the box, immediately beneath the lever-frame, and invisible from the box. It varies in construction according to the different manufacturers. It consists generally of a lot of notched iron rods being crossed with others working conjointly with the lexers above. They are arranged so that when a signal is pulled off for a train to pass, the lever that works it also works the locking gear underneath in a way that all other levers-applying to switches on the same line are locked. Hence it is impossible to move a pair of switches when the signals are off for a train to pass.

On the other hand, no signals can be pulled unless the road is set right, and the sw itch levers properly' secured in their normal position. So intricate is this system of interlocking that, even if a switch-lever is nos properly put ba-ck and securely fas«

tent-d in its slot, the signal-levers cannot ba pulled. In short, the interlocking system may be justly termed the grandest thing in connection with railway signalling. Next in order comes the block-telegraph system of signalling. All signal-boxes are furnished with telegraph instruments and bells to signal from box to box for each line of rails ; but the system under which these are worked, and the mode of indicating the description of trains, would fill m volume. ' Therefore, let a few principal facts suffice.

A, B, and C represent; three consecutive signal-boxes, and tlie process of signalling a train is as follows :

When a train is ready to leave the start-ing-point, A. the signalman, by means of the electric bell, calls the attention of B, and then gives the prescribed, "Is line clear?"' bell smd instrument signals. If the lino be clear, these signals are repeated back to A, and the needle of the instrument fixed to " Line clear." The signalman at A then pull? off his signals for the train to proceed, and, when it leaves, gives the " Train entering section " signals to B. B then turns the needle of the instilment to "Train on line," ir which position it is kept until the train passes B, and is travelling at its usual rate of speed, with taillamps on. These show that the train is

complete, and that no part has become detached.

Being thus assured all is well, the signalman at B gives bach to A the " Train out of section signal, and places the needle of his instrument in its usual position — A^ertical. Each signalman asks, " Line clear?" to the box in advance when the train leaves the box in the rear. In this way the trains are signalled throughout the line. By the strict observance of these rules, which are rigorously, enforced, it is absolutely impossible to -have two trains in the same section at the same time.

Another thing "which often puzzles the public is how the engine-driver picks out hi.3 signals and speeds along through the stations and yards with such confidence in those guiding lights. A few words on the subject may, perhaps, be acceptable. The ingress and egress of stations is controlled generally by foui signals — namely, " Distant," " Home," " Starting," and " Advance starting." The driver sights the " Distant " first — it is distinguished from the others b}' the outer end of the arm being swallowtailed in shape. It is the only signal that may be passed when at danger. Should this signal be at danger, the driver reduces speed, and proceeds cautiously to the next, being prepared to stop if necessary. Should it be off it indicates to the driver that all the others are off also, for, by the interlocking just explained, this signal cannot be pulled before all Ihe others are pulled. Hence the speed through stations. The " Horn? " signal controls the entrance -into thtt station; the "Starting" signal and "Advance starting" signal control the fta-

parture into the section ahead for the next station. Signals, as a rul«, are so placed as to indicate by their positions the line's to which they apply, generally as follows : The first, o" top, arm to the line on 'the left; the second arm to the line next in order from the left; and so on.