I actually own the wood replica made by Holgate. The longer I have it, the less I like it. Just being honest. It was clearly intended to be nothing more than a child's toy. It was an impulse buy. I spotted it at a store and had to have it. That said, I think I have answers to some questions.
The original trolley was built by a friend of his as a good luck present. Mr Rogers decided to incorporate it into the show as a metaphor. It is just balsa wood, aside from the mechanicals. The whistle in the front does nothing. I believe the mini models of the neighborhood of make believe were also made by a friend of his. Not sure if it's the same one....
If you have Netflix as of this posting, they have episodes. The first of which, when he brings the trolley out, he picks it up to show the wheels and say the trolley is just a toy.
At last I saw or heard, the actual trolley was on display when they recreated the set for a special event. Hasn't been seen since. The history center only had the Holgate replica.
I just yesterday ordered a Bachmann G scale trolley. I need a project and I'm going to modify it into our friend the neighborhood trolley, then eventually build the bench he sat on. Mine will even have the dummy whistle.
Here's an amazing replica someone made as well.
http://neighborhoodarchive.com...7_trolley/index.html