Yeah, I figured that the small wires are acting as "fusable links" but is sure seems a silly way of doing things. and I doubt if it is "intentional".
And, yes, I understand that some power supplies are fused and that certainly protects the power supply from a dead short on its output. But I keep seeing comments here on MLS about fried drives in locomotives caused by it being stalled and drawing too much current.
Fusing the power supply at its safety limit may not be protection for the loco. If the power supply limit is below the damage limit of the loco then the loco is protected. But most folk have a supply that can provide much more current than what the loco ever will need or, more importantly, what can damage it. This is because they also run lighted cars, and/or multiple engines, and/or other things that draw power from the same supply...
example:
A loco might draw 5 Amps when starting (or near stall) and, say, 4 (lighted) passenger cars draw 1 Amp each (all estimates for maths simplicity here). This means the supply must be capable of supplying and be fused for at least a wee bit more than the sum of all the current needs, or in this case, about 10 Amps. Now if the passenger cars all derail and the loco traverses the whole system and collides with the derailed consist from the rear (I assume the scenario that started this thread) which causes it to stall and it then draws, say, 9 Amps. At this point, the power supply is perfectly happy to let the loco burn to a crisp.
I have never been a fan of the use of "fusable links" in the automotive world as I have seen the result of one of them setting fire to the engine compartment of the car with the resulting total desctruction of the whole car.
Oh well, mine run on alcohol so I don't really care!
