Commercial-Frequency A-C Electrification for a Rapid-Transit System

A practical method of applyring 3-phase 60-cycle power directly to a rapid-transit system is described. An unconventional distribution system is used to overcome the high impedance of the magnetic third rail. The problem of phase-unbalance, sectionalizinlg, controlled-rectifier traction, motor control, current spikes, and regenerative braking are presented with practical solutions for each of these problems. A very rough estimate of savings in first cost and annual energy consumption are tabulated.