A new control for heavyweight rapid-transit cars

An advance over the original combination of electric-operated cam controller with pneumatic circuit contactors, this new system utilizes two motor-operated controllers; one to establish main circuits, and the other to commutate resistance. Refinements, introduced as the result of operating experience with equipment of the previous type, give smoother operation and improved dynamic braking characteristics. Compactness and ease of maintenance have been achieved to a marked degree.