I guess that no one else is going to point out that carrying or using a shunt is DANGEROUS TO YOUR HEALTH. The reason is that the railroad police would probably interpret this to mean that possession of such a device (especially on railroad property) when the person is not a railroad employee, shows that the person has INTENT to tamper (with signals) or is trespassing with intent to tamper. This is cause to ARREST the person. It is similar to being on the property while possessing a switch key. It shows trespassing with intent to tamper with a switch.

An additional reason to avoid shunts is that it is very difficult to reliably shunt the rails without the proper type of clamps. The clamps on battery jumper cables are not the type that will reliably make the necessary contact, if they make contact at all.

Even IF the rails WERE reliably shunted, an approching train may have already passed the last signal in approach to the shunt and would be approaching the shunt at TRACK SPEED.

The possession of fusees (as long as they remain in the vehicle prior to emergency use) does not show intent to tamper, since they are normal equipment for highway use.

Always keep in mind what the railroad police MAY construe or interpret.