Thanks for posting the link, Jim. That's a dedicated group of folks over at the Baltimore Streetcar Museum. Haven't been there for awhile, but I used to take my kids once each year back when they were young. I don't think we ever rode the same motor twice. Back then, they were fortunate to still have guys on-hand that had actually worked for the Transit Company; not sure if that's still the case.
There's quite a bit of the streetcar infrastructure still around. One of my favorite buildings in the city was the old Baltimore Traction Company's power house originally built for the Druid Hill cable railway. Most of it has been torn down, but a chunk remains:

A Romanesque Revival style building, it was a spectacular pile in its day. Located at the corner of Druid Hill Avenue and Retreat Street, it's mostly a vacant lot today in a part of the city that looks like Dresden in 1945.
Another repurposed building is the old power house and car barn that now houses the Charles Theater, and of course there's the "Power Plant" at the inner harbor that was built by a predecessor of the United Railways & Electric Company for power generation. The massive car barn over on Washington Blvd. now serves the MTA bus fleet, and throughout the city, there are still street-side shelters built by the transit companies, some of which now serve as bus stops.

There's still a lot of remnants around.