In the event of a big derailment like that, is there a way to tell all the locomotives (including the DPUs) to engage an emergency fuel cutoff/engine shutdown in a similar way to an emergency brake application? I also wonder if modern locomotives have a fail-safe mechanism inside that does this automatically in the event a locomotive tips onto it's side..... similar to the tip sensors that turn off space heaters if they are tipped over in a house. Maybe it shuts down when the engine systems start detecting oil starvation to the engine due to it being on it's side.
Also on DPU signal loss. I'm guessing unlike the early days, today's systems rarely lose signal in mountainous regions due to repeaters along the route. But in the event the DPUs were to lose signal, how exactly does the DPU handle it? I'd imagine it has a time-window buffer that allows it to keep running for say.... 20 seconds without a signal before reducing power in the chance that it can reacquire the signal in that time. My guess would be that it's also speed dependent. Cuz a slower train would need a longer time window to reacquire a signal than a faster train before reducing power. Maybe it goes by how many feet it can travel without a signal before disengaging. That would solve the speed issue.
And when it does power down due to signal loss..... does it reduce the power to zero instantly or does it notch down in steps? Does it also apply brakes and if so... is it slowly or very quickly similar to an emergency brake application?
These are things I don't hear the details of too much and was just curious.
