[ccmmick]

Hi Jim
It is quite simple the loco switch was left in vacuum so you had 21" of vacuum the loco still had main air at 72.5 PSI to provide the air brake wagons they were behind the loco with the vacuum blow through white (pipe) coupled to provide the back of the train with a vacuum brake.
The brake test was done on the rear of the train in the normal way ie a vacuum brake test.
You didn't have to pull any release cords as in theory you had two trains in one air and vacuum together.
You could only do this with a few air wagons as the loco in the vacuum postion only has one compressor working when the loco is worked in the air postion you have two compressors working feeding a train.
Like i say it was not allowed to work a train in this way, we did only to save time and one trip to Penzance instead of two trips and it went on for quite a few months untill management got wind of it, we didn't get in any trouble we were just told not to do it anymore .

ccmmick.