H0 Marx? The little bit of their smaller stuff I've seen looks pretty neat. I've only got an F unit and I don't believe it runs (everything else in that collection had smoked motors; there was a Variac transformer with them that put out 0 to 120 volts...)
I wouldn't mind hearing about them or better still, seeing a few pictures of them. I couldn't help you with values or rarity though.
J White