The Connecticut Company had a high rail bus built in 1967 for use on streets in downtown, then onto rail lines for quick travel to the suburbs. The bus remained in the fleet for several years and occasionally went on demo runs. I rode it several times in the 60s and 70s. But the state showed no interest in building more or using the original one, so it wound up at the Connecticut Trolley Museum in Warehouse Point. Here's a link to a photo of the bus, but the railroad wheels don't show.
Lee Carlson