TO AVERT RAILWAY SMASHES.

Pelorus Guardian and Miners' Advocate., Volume 23, Issue 7, 26 January 1912, Page 2

TO AVERT RAILWAY SMASHES.

MECHANICAL BRAINS TO SAVE LIVES. The President of the Board of Trade has expressed the opinion that there is no need for a second signalman to be placed in every box, says “Science Siftings,” and that the present block system obviates any risk of accident in the event of the illness or death of the man on duty. But there are too many railway wrecks ! How shall they he made less frequent ?■ Much may be done to lessen the number of such accidents by the adoption of certain mechanical measures of precaution —most important of all the automatic train-stop. Such a stop provides for automatic train control. It is a device to prevent the over-running of stop signals by drivers. Often it happens that the engineer of a locomotive fails to notice the fact that the signal is set for' danger. It warns him to bring his train to a halt ; but, failing to recognise it," he runs past, and in many instances a disaster is the consequence.

The ingenuity of inventors has been taxed to devise a means by which this sort of mistake may be. avoided. They have contrived a number of expedients by which an over-run danger signal gives warning in the cab of the locomotive, automatically. They are called '“cab signals.” Other devices, which not only give warning, but actually stop the train, are still more effective, reducing the human factor in the railroad equation to a minimum.

In most instances they are electrical contrivances, and operate by setting the brakes of the train. Thus, for example, one of them is an arrangement whereby a danger signal cannot possibly fail, if over-run, to strike. and smash a small glass tube rising from the top of the motorman’s box. In case he does not see, or neglects to obey, the warning, the breaking of the tube opens the airbrake valve and sets the brakes. Two. devices which have been tested under actual ■ traffic conditions, are both of the mechanical trip type. One of them, known as the RowellPotter train-stop, is an arrangement by which a bar lying parallel and close to one of the rails, is lifted a short distance above the rail whenever the visual signal is set for danger. Under such circumstances, the bar, coming into contact with an air-brake valve, suspended from the tender, opens the valve and applies the brake. Bars at the side of the track are provided in duplicate at each signal point, one of them 180 feet in advance of the other, so that, if the first one should by any accident fail to operate, the second would bring the train to a halt. Power •to operate the stop, as well as to work the semaphore signals of the system, is derived from the pressure of the wheels of the passing trains on levers fixed close to ' the rails, these levers serving to wind up a coil spring. Another automatic, stop works "overhead”—that is to say, the device fixed at the roadside is suspended, some feet above the line, in such a way as to come into contact with a projecting arm of .an air-brake valve on top, of the cab in the locomotive, the opening of which valve applies the brake. The roadside contrivance consists of a weight suspended on the end of a chain, which, hanging free, operates the engine valve by its mere inertia, when it strikes. At the same time, it has the great advantage of failing to work when a t|:ain is going very slowly—say, five miles a n hour or less. Under such circumstances—when a precaution of the kind is not wanted—the weight need simply drag over the operating - rod on the locomotive, . producing no effect. It will be observed that the automatic stop does not in any way in-, sure the correctness of siganls. Its only function is to correct the error of the engine driver who funs past a danger warning. This, however is of utmost importance, inasmuch as many bad accidents are caused by the failure to observe and obey signals that are properly set, There have also been. devised cab signals, to which a n automatic trainstop can be attached if desired. One of these is now in use bn the Great Western Railway. Its essential feature is a short contact rail in the middle ‘of the track at the signal point. This rail engages with a device beneath the engine, showing a danger signal in the cab and blowing the whistle of the locomotive.