Substations
There are in operation for supplying power to both elevated and surface lines a total of 12 synchronous converter substations having a total rated capacity of 58,000 kw. The power consumption of the Rapid Transit lines is somewhat less than half the total energy used.
Distribution
Direct current is distributed from the several substations at 600 volts and is collected on the rapid transit systems from an 85-lb. over-running third rail.
Rolling Stock
Altogether there are 420 cars in the rapid transit service, the older cars weighing about 34 tons with seating capacity of 48 and the newer type as used in the Cambridge Subway 43 tons each, arranged to seat 72 passengers. On account of the limiting clearances in the old subway the Cambridge cars cannot be used on the main line. All cars are motor cars and no attempt is made to use trailers. Each car is equipped with two motors and multiple unit control.
Latest Type of Steel Motor Car Used in Cambridge Subway
Main Line Train—Boston Elevated Railway