500
EXPOSITION AT VIENNA.
it comes into place, the fault, though not revealed by the working of the switch-lever, will be detected when the locking apparatus is used, since that lever cannot be drawn, unless the switch is correctly placed.
In all these contingencies no harm can result, since a train will always be stopped by the " danger ” signal before reaching the switch. The apparatus, in short, besides insuring safety when it is in order, is a guard against any derangement in itself.
Since its adoption in England, but one accident has occurred, out of the many which have been attributed to switches, at a point where this system is in use. This is important in view of the fact, that in the (English) Board of Trade report on accidents in the year 1871, Captain Tyler attributes the majority to defective signal and point arrangements, or want of locking apparatus. The Wigan disaster, last summer, on the London and North-western line, is the exceptional instance. An excursion train passing over facing points was divided, and the majority of the cars went off the track entirely, or else on to a side track. The mechanism for moving the points had been inspected shortly before, and was found uninjured after the accident. The points were also found to be placed rightly for the transit of the train. As near as I have been able to ascertain, the locking apparatus described above had not been applied at this point, though in use on other parts of the road. Whether the accident was caused by the faulty action of the switch mechanism, or whether the signal-man attempted to move the switch before the train had all passed over, it is impossible to decide, before the court of investigation shall have published its conclusions. It seems as if a properly constructed locking apparatus would have fastened the switch, and would have effectually prevented any change in its position. The value and necessity of some such system is unquestionable. It is for American engineers to decide to what extent the one described is applicable upon our railroads.
ELMER P. HOWE.