Electrical equipment of track on the underground railways of London

The paper gives a few historical facts leading to the adoption by the District Railway of 600 volts direct current with the insulated return, and makes reference to thestarting up of the Tube lines. It also deals with:¿ Some results in working the insulated-return system. Conductor rails; material used, section, conductivity, loss of weight, anchoring, and data with regard to the painting of rails. Types of insulators used and data with regard to cleaning and insulation. Injurious effect of electric burns on track rails. High-tension cables. Maintenance of track equipment, including methods adopted forclearing ice or snow from conductor rails. Operating arrangements for removing and restoring current. Some particulars are also given of certain special instruments used by the Underground Railways. The conclusions reached by these Railways are set out at the end of the paper.