Wednesday, July 15, 2009
M.U. wiring complete
Another big wiring job completed is the multiple unit wiring. This is the 12-pin jumper plug discussed earlier, and its numerous connections throughout the car.
The multiple-unit control plug carries signals which control forward/reverse, series/parallel and the various resistance points. This wiring must go to a remarkable number of places on the car. On each end, it goes to three places - motorman's control stand and also to two jumper plugs. The seventh connection is to the switch group which actually controls the car's motors.
These connections happen in three control boxes - one at each end and one in the middle of the car. The end control boxes connect to the motorman's control stand, two jumper plugs and the middle control box. The middle control box connects to the end control boxes and to the switch group. With 12 wires per connection, it gets pretty crowded in those boxes!