The Roundhouse is a restored railway building in Yaletown, where Vancouver's old railyard has been folded into a dense modern neighbourhood. Its best reason to stop in is Engine 374, the locomotive that pulled the first passenger train into Vancouver in 1887.
The building now works as a community arts and recreation centre, so the feel is local rather than museum-polished. Even so, the roundhouse itself and the locomotive make a good short stop if you are already walking through Yaletown.