— Ray Russell, Naples, Fla.
A “Isolating” a particular locomotive in a multiple-unit consist means that the prime mover is still running, but the main generator and electrical system for propulsion are disconnected. The locomotive will not respond to throttle settings and essentially is along for the ride, although it will have current for auxiliaries (light, heat) and continue to make air for the brake system. The large ring gears on the axles are permanently meshed with the small pinion gears on the traction motor armature shafts, so the motors will be spinning at roughly the same speed as the motors on the working locomotives. But because none of the motor circuits are energized, they will essentially be “free wheeling,” just as they do when a locomotive is hauled dead in a consist.
— John Hankey, railroad historian
what is the process of DIC or DIT ?