Running Rails Research Articles

A Modern Cab Signaling and Train Control System for Railroads

Increased safety of train operation is effected by the continuously controlled cab signal which may be augmented by means for applying the brakes automatically in case cab signal changes calling for a reduction in speed are ignored or pre-determined speed limits are exceeded. The engine-carried apparatus is inductively linked and selectively responsive to coded alternating current in the running rails, the frequency of coding determining the cab signal indication displayed and being dependent upon traffic conditions ahead. Absence of rail current or the presence of uncoded current establishes the most restrictive speed conditions.

Electric traction on the Southern Railway

The paper gives the first comprehensive description of the complete scheme of electrification of the Southern Railway. The system of electrification is 660-volt direct current with a top-running-contact conductor rail. The return circuit is by way of the running rails. Threephase electrical energy, generated or purchased at 11,000 volts, 25 c/s, and purchased at 33,000 volts, 50 c/s, is stepped down and converted to direct current for traction, by means of rotary-convertor and mercury-arc-rectifier substations. The paper includes some historical remarks, reasons for electrification, and results. It describes the power supply arrangements, the cable transmission system, the substations, the track equipment, and the electric vehicles. Particular attention has been given to the more modern equipment, and there is some amplification of detail on matters of unusual interest. Operating features that are of interest follow descriptions of the equipment to which they relate. Construction was stopped by the outbreak of war in September, 1939. The paper deals with developments previous to that time, but the electric locomotives completed subsequently are briefly described.

Testing Steel Rails

A DESCRIPTION is given in the Electrical Review of November 22 of the method developed by Sperry Products, Inc., Hoboken, New Jersey, U.S.A., for examining steel running rails of railways in situ for internal defects. A recording car is used, and operation is based on the fact that any internal discontinuity in a metal bar creates an area of high resistance to the flow of direct current; consequently a difference of potential will occur at the site of the internal flaw. Indicating currents are conveyed to the track rails by brush holders attached behind the front bogie and underneath the frame of the rear bogie of the coach. A current of about 1,500 amp. up to 8 volts is injected for pre-energizing the rails to ensure uniformity of molecular arrangement prior to the introduction of the detecting current just in front of the two pairs of searching coils. This precaution is necessary because running rails are generally magnetized by the normal effect of the earth's field, augmented by vibration due to the pounding of passing train wheels.