Fig. 1.
Robinson's Closed Rail Circuit System. Philadelphia & Erie Railroad, 1872.
As all the signal apparatus, relays, batteries, office switches and overlapping devices were already in operation there, it took but a short time to convert this open circuit system into a closed rail circuit system.
The first experiments proved conclusively that the system would work. The track, however, was in a fearfully unsuitable condition for the purpose. The light rails were fished together by a four foot wooden bar on the outside, and a twelve inch fish plate on the inside. There were two holes through the iron fish plate, allowing one bolt for each rail and four holes through the wooden bar, two for each rail. However, with a little care he managed to get the current working through the whole length of the section about a mile and a quarter in length.
It was evident, however, that on such a section as this a rail bond of some kind would be necessary for reliable, continuous service, and here, at this time, in 1872 Mr. Robinson conceived the invention of the bond wire method of electrically connecting the rails, now in universal use, or its equivalent, on every electric railway throughout the world using the rails for a return.
As it had been determined to lay new rails at Kinzua, another installation of the closed rail circuit system was ordered and immediately made at Irvineton, Pa. This signal is illustrated in Fig. 1.
It will be observed that the above installation, like that at Kinzua, not only displays a visual block signal, but also operates in connection therewith a loud gong which has been easily heard at a distance of a half mile, and was really heard by passengers in trains passing, with closed windows. An engineer could not possibly pass without hearing it.
A wire is seen at the upper part of the signal box, running out to the right. This is an overlapping signal wire.
A tell-tale bell was also placed in the station, indicating the actual position of the signal, and also a manual switch, whereby the agent could at any time cut off or short circuit the track battery and expose the danger signal against a train and instantly receive a return signal when the danger signal was actually exposed.
The Irvineton installation worked perfectly from the first never failing. The locomotive engineers were delighted with it and soon gave it the name of "The old reliable."