Here's a test fit of the Bachmann trolley poles. I will shorten them a bit, but I like them. They are a bit pricey but very nicely made.
Steve
They're too pricey for me to be using two per trolley. I still say one mounted in the middle and allowed to pivot is prototypical, it was common on early trolleys and the operator got out and turned the pole around when the trolley was to head back in the opposite direction. From the wiki article on trolley poles:
"On systems with double-ended tram cars capable of running in both directions, the trolley pole must always be pulled behind the car and not pushed, or "dewiring" is very likely, which can cause damage to the overhead wires. At terminus points, the conductor must turn the trolley pole around to face the correct direction, pulling it off the wire either with a rope or a pole and walking it around to the other end..."
You can make a hook in one of the roof's end holes, to hold the pole down when necessary, you won't need to shorten it.
The Bachman ones are all metal and well made, they seem very appropriate for tinplate use.
david