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REPORT OF MR. HOWE ON RAILWAY SWITCHES, ETC. 499
the platform on the other side. This is the most complicated movement that is required, and involves an alteration of about twenty-five switches and signals. Information in regard to the arrival and departure of trains is communicated to the signal-men by telegraph. The despatches are received by two instruments, one at each end of the glass house. One apparatus rings a bell; a boy in attendance consults the index, and immediately calls out the name of the train which is to come over the bridge into the station; the proper movements are made by the signal-man as soon as the train appears, and it enters the station without delay. The other telegraphic instrument is for the general business of the road. All messages received are noted, so that an accurate record of the movements of trains is kept. By means of this Saxby and Farmer system, in this compact arrangement, the immense business at this point is transacted with speed and safety, with astonishing ease and precision. In the old way, with isolated switches and signals, at least thirty men would be needed, and the greatest care and attention would have to be exercised to avoid accidents.
It remains to consider the durability of the mechanism, and what may occur if any part should break. Since the normal position of the semaphores is at " danger,” the breaking of a signal-rod would either leave the arm unmoved, or it would return by its own weight to the point indicating " danger.” Therefore, no break or derangement of the semaphore mechanism can occasion anything worse than delay. As there are a number of rods and bell-cranks used to convey the motion of the manipulating lever to the switch proper, quite an expenditure of force is required to overcome the friction. Now, if a part give way, the increased ease of operating the lever would make it evident to the signal-man that something was wrong, and he would therefore leave the signals unchanged. Here, again, no evil consequences would result. If any considerable obstruction should prevent the moving of the switch into its proper position, not only would it be evident to the signal-man, but he could not move the lever far enough to unlock the signal-levers, even if he desired to do so. When there is " lost motion” in the connecting tackle, or when dirt and snow stop the switch before