Cab Signaling Research Articles

Abridgment of shunting of track circuit in a polyphase system of continuous inductive train control

Investigations into shunting of train control track circuits have been made in the field under operating conditions by observing the operation of the primary relay on a locomotive as a train runs into a track circuit' in which there is a train ahead or an open switch and similar data have been obtained on the performance of the relay on trains in regular service. It is intended in this paper to present a method for predetermining the shunting characteristics of train control track circuits. The system discussed is a polyphase system of continuous inductive train control with cab signals employed on double-tracked steam roads. Curves are given which describe shunting conditions in train control track circuits and data are also given for comparison describing the shunting of the track relay on the same sections of track.

Discussion at Kansas city meeting: Development of railway signaling

F. E. Snell : Though continued development of the semaphore and light type of signals resulted in the production of a highly efficient unit, it yet has some serious drawbacks as pointed out by Mr. Stevens. These unfavorable conditions, attendant on wayside signals, which could not be remedied by electrical means, naturally resulted in the development of a cab signal. The cab type of signal may also offer a solution to one of the problems with which we are confronted in Cleveland, and which, no doubt, affect other operators of rapid transit lines in metropolitan areas, where a portion of the right-of-way is through the less polite residential sections. I refer to the malicious destruction of signal equipment by trespassers, particularly small boys who throw stones, using the wayside signal light lenses as targets.

Cab Signals for Railway Signaling

There is described in this paper a system of continuous signals operating within the cab of a railway locomotive. This system was developed in an effort to provide more reliable and safer signals than the common semaphore or light signals. The particular type of system is called the three-speed, continuous-control signal system. It has been adopted quite extensively by the Atchinson, Topeka, and Santa Fe Railway System.