RAILWAY SIGNALS.

New Zealand Herald, Volume LVIII, Issue 17956, 5 December 1921, Page 8

RAILWAY SIGNALS.

NEW ELECTRIC SYSTEM. OPERATION IN WELLINGTON. Signs! appliances which are now being erected along the railway line between Wellington and Upper Hutt are of a class flew in this country, and are operated electrically, without human intervention. With this system, a line can be fitted with signals at short intervals, and it is possible to have a train on each section of line between adjacent signals. On', each post is a small electric motor, geared to the signal arm, apd the method of operation is that when the line is 'clear for traffic the apparatus receives current, and the motor brings the signal arm to the "clear" position. "** If a train enters the section controlled by a signal, the .current, which is carried by the rails, is switched off from the relay controlling the motor by traversing the wheels and axles of the train, aha the signal promptly falls to the "stop" position. At the same time the signal next behind the advancing trajn, which, was previounly at " stop," is operated by a different set of electrical connections, and moves to an intermediate position which warns the driver of a following train that he is to proceed With caution. Any mishap, which prevehts» current reaching the signal motor, such as a break in a rail, or the failure of any of the electrical apparatus, will cause the signal to fall to the " stop" position, The " clear" position can thus only be given when there is no train on the section of line, and Wh6n the apparatus is all working properly. An important difference between the present signals and the new ones is the introduction of the third "cautionary" Eosition. The manual signal arms point orizontally for ".stop," and are dropped to an angle of 45 degrees for'" proceed." The new signal will be horizontal for " stop," and will rise to an angle of 45 degrees for " caution," and to a vertical position when the line is clear. The night signals are also varied. Bed now signifies stop, and green clear. With the new installation the same colours will be rotained, with the same meanings. For "caution" a yellow light will show, coloured glass used for these yellow lights has been specially made so that the light which passes cannot be mistaken for either green or red, even by people with bad j colour perception. The coloured glasses I are attached to the signal arm. so that ( they come in front of a fixed white light, , as in the oldw signal apparatus.