Red end of train device

[storminorman]

The other weekend I was sitting and waiting on a slow moving train when both my son & I heard a higher pitched sound as the end of the train passed. He said he has heard it before. Made me wonder if the red light on the last car is powered off the air line that drives a small generator.

 

[Crow]

That is exactly how it works. They use to use batteries, but it was hard to ensure they had a full charge for the entire trip. Typically air brake rules allow for 5 psi of leakage from the head end to the rear end, so why not use a small leak to run a generator to power the light and the radio, and you never have a dead battery.

 

[RCH]

Never say never. I had one of the new UP ETDs this morning that worked from the air, but had a dead internal battery. Fortunately, it was daylight and I was only making a transfer move so I didn't need it for any reason other than the air test and as a marker.

 

[Chris de Vries]

Never say never. I had one of the new UP ETDs this morning that worked from the air, but had a dead internal battery. Fortunately, it was daylight and I was only making a transfer move so I didn't need it for any reason other than the air test and as a marker.

And it just takes about 15-20 minutes of air to it to charge it up. That happens quite often if the SBU is not plugged in to an electrical outlet when not on a train.