On a typical "modern" (ie late 20th century) train like the mainline EMUs I would normally catch when I was a commuter decades ago, the equivalent "cut out" is a glass sealed MCB in the cab, a driver who wants to get rid of this safety feature has to destroy a tell-tale glass seal and company regulations will make them write up why it was necessary then replace it - and of course the automation records each occurrence because why wouldn't it. The paperwork is a faff, so is getting a new unique numbered seal, so drivers actually choose the non-risky option when it's available.
On the steam loco, that "cut out" is operated by cutting a cable tie. The cable ties aren't unique of course, and so investigators found countless broken ties littering the dirty cab of the steam locomotive, because you just cut the tie, do what you want and before signing off try to remember to fit a new cable tie. No actual safety delivered.