UK Rail and Trains

234 readers

8 users here now

Talk about the UK rail network.

founded 1 year ago

MODERATORS

Mex

[Video] Why does it take so long for this Class 50 to start up when cold? (www.youtube.com)

submitted 6 months ago by blackn1ght to c/rail

11 comments fedilink hide all child comments

It seems to take nearly 10 minutes to get started. What's actually happening? Are the pistons literally unable to move in the cylinders until the engine is warm enough?

you are viewing a single comment's thread
view the rest of the comments

[–] JamesTBagg@lemmy.world 4 points 6 months ago (1 children)

I don't know anything about this particular diesel engine but can hazard some guesses.

It's probably old and tired and not making compression like it used to; diesels fire by compression ignition. That engine is turning freely, otherwise it wouldn't be pumping any air.
Old diesels without glow plugs need to work up some heat in the heads to get combustion going.

All that white smoke is unburned diesel, just aerated fuel getting pumped through the cylinders. The starter (compressed air or electric) is probably doing a lot of work here to generate heat in the cylinders via compression. If it's supercharged it may be struggling to build boost in the intake side. Later the dark black puffs is partially burned fuel... it's starting to fire off. The exhaust smoke seems to be shifting from white to gray. I'll bet a dollar once she gets running that exhaust will clear right up.

[–] snaprails 1 points 6 months ago

“That exhaust will clear right up” I’d be surprised if it did, even when they were newish Class 50s could produce an impressive plume of exhaust smoke. When I was a kid spotting on the Western Region main line and these were in regular service we learned not to stand directly above them on the footbridge at the station 😀 They make a great noise going at full chat though.