bramling
Veteran Member
A bit off topic I know but I saw a surviving 317 in the depot adjacent to platform 8 at Cambridge with lights off and no sign of life. Every couple of minutes the engine fires up and makes a loud 317 rattling noise for 10s or so before going off. What is that noise? Why is the train still doing things when it appears off and has no driver? Always wondered! Thanks.
Sounds like the compressor, which will kick in when the main reservoir falls below a certain level. If it's coming on regularly when the train isn't doing anything then there's probably air leaking away.