This section is from "Scientific American Supplement Volumes 275, 286, 288, 299, 303, 312, 315, 324, 344 and 358". Also available from Amazon: Scientific American Reference Book.
To the Editor of the Scientific American:
I send you a plate of my new railway signal wire compensator. Here in India signal wires give more trouble, perhaps, than in America or elsewhere, by expansion and contraction. What makes the difficulty more here is the ignorance and indolence of the point and signalmen, who are all natives. There have been numerous collisions, owing to signals falling off by contraction. Many devices and systems have been tried, but none have given the desired result. You will observe the signal wire marked D is entirely separated and independent of the wire, E, leading to lever. On the Great Indian and Peninsula Railway I work one of these compensators, 1,160 yards from signal, which stands on a summit the grade of which is 1 in 150; and on the Nizam State Railway I have one working on a signal 800 yards. This signal had previously given so much trouble that it was decided to do away with it altogether. It stands on top of a high cutting and on a 1,600 foot curve.
Railway Signal Wire Comensator
I have noted on the compensator fixed at 1,160 yards, 13¼ inches contraction and expansion. The compensator is very simple and not at all likely to get out of order. On new wire, when I fix my compensator, I usually have an adjusting screw on the lead to lever. This I remove when the wire has been stretched to its full tension. I have everything removed from lever, so there can be no meddling or altering. When once the wire is stretched so that no slack remains between lever and trigger, no further adjustment is necessary.
Chief Maintenance Inspector, Permanent Way,
H.H. Nizam State Railway, E. India.
Secunderabad, India, 1881.