Being a tinplate train nut....
My memory was they were not cheap, but I do remember Sidestreet Bannerworks (Mark Horovitz of "Garden Railways" magazine fame) used to sell them in the 1980s along with being the US agent for Roundhouse. They were some strange gauge which Marc warned you was "compatible with absolutely nothing". The manufacturer started with an "F", Fontanya, Fontain, etc.
Alyn, are they still available, where did you find this? I saw one set sell for stupid money on eBay a while back, and forgot all about them until now.