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| Re: Holiday Train Cancelled Today Dec. 3, 2016 (1419004) | |||
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Re: Holiday Train Cancelled Today Dec. 3, 2016 |
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Posted by randyo on Thu Dec 8 21:17:44 2016, in response to Re: Holiday Train Cancelled Today Dec. 3, 2016, posted by Steve B-8AVEXP on Wed Dec 7 20:10:53 2016. Although it wasn’t supposed to have anything directly to do with the door circuits, on the steels, the brake plug was involved with the door operation to a certain degree. One of the interesting aspects of the steels was that the guard lights did not illuminate if the brake plug were not inserted. Also, the steels required 2 keys for the C/R to operate the doors: the ground key which was inserted in the panel under the button board. Although the ground key was inserted on only one side of the car, it energized both button boards. The other key was inserted in the button board itself and enabled control of the doors on that side of the car from that position. If the C/R inserted the ground key first and the M/M inserted the brake plug, the doors on that side of the entire train would close so we were instructed that the button board key was to be the first in and the last out. I have a brake plug receptacle from a BMT steel and it only has the standard 3 contact fingers for battery, application and release and no additional contacts relating to the doors, so somewhere, along the development of these cars, additional circuits were a added to the existing ones, when MU door control was added to the cars in the 1920s. possibly. As delivered, the door controls on the steels only operated the doors in each individual car with MUDC only being added around the time the cars were unitized into B and BX units which also explains why a jumper under the coupler was necessary for MU door operation since there was no additional room for contacts to be added to the slides (electric portions) on the coupler. |
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