I just wanted to circle back and report:
Choo Choo Bob has been a huge hit! Wonderful show, love the wittiness, and offers a nice bridge between models and the real thing. It's a shame they didn't make more seasons. He basically plowed through all the episodes in a couple weeks, but I think they will be seen again and again.
Also the "Railroad Alaska" show has been a big hit. Unfortunately it suffers from the same flashy/dramatic production of the "Extreme Trains" series, but the content and scenery is good, and he is really drawn into the work that the track gangs and train crews accomplish. There is a lot of swearing, which is bleeped, but with the hamming-it-up/camera-drama it's distracting (for me). Overall I think the beautiful Alaskan wilderness backdrop makes up for it, and he is learning a great deal.
We tried watching a few other things, but these two are the ones he is most into. Last weekend we visited the Midwest Railway Preservation Society at the old B&O roundhouse downtown to see the Reading 2100 restoration, and he was readily identifying parts of the locomotive for the crew, haha.
