REPORT OF MR. ROBERT B. LINES.
475
This current first actuates a bell-sounder at Barnes (Fig. C) in the ordinary manner, announcing the approaching of the train from Putney. In addition to the ordinary hammer- armature, however, there is a permanent magnet M swinging between the poles of the electro-magnet, as shown in Fig. D. When the battery from E is on the line, this magnet swings over to the left, and when the battery from F is on, it is then thrown to the right, in consequence of the different polarities given to the electro-magnet by the change of the direction of the current. The axis of this permanent magnet is prolonged as in the Italian switch-control heretofore desoribed (see Plate V.), and works a rack and pinion movement, shown in the cut, which controls’ a needle-indicator on the outside of the case. The movement of the indicator is, of course, the reverse of that of the magnet. (Fig. A.)
The permanent magnet at Barnes once thrown to "off” by the signal-man at Putney, is not again disturbed except by a reversed current from the battery through E, which cannot be put on the wire while the semaphore at Putney indicates "line clear.” Any number of signals may, therefore, be made on the bell at Barnes indicating the character, etc., of the approaching train.
But as soon as the train has passed Putney it is necessary that his semaphore should be blocked. The signal-man at Barnes, therefore, acknowledges the receipt of the information of the approach of the train by throwing his switch-lever over to "on.” This releases the armature lever B of the magnet at Putney, and the semaphore at Putney indicates "arrest.” The man at Putney then blocks his out-door signal to correspond, and again depresses the plunger b to show that the signal from Barnes has been acted upon. This, however, throws the current from E instead of F upon the bell-wire, and the indicator at Barnes marks "signal on at Putney.”
The system of check and control in the working of this apparatus seems to be complete. No one signal can be given and acknowledged without the concurrence of the signal-men at both stations, and the chance of accident through its fault is reduced to a minimum.
The system Tyer is in use on several of the English railways, and on the Lyons and Eastern railways in France, and