Stan, I remember seeing one that had only one outrigger wheel many moons ago, I can not remember where it was, I do remember the guy telling us that the 3 wheelers were favored as they were easier to remove from the track if they heard a train coming,
and some years ago, one of the magazines ran prints on how to make one out of a bicycle, of course
train traffic was not heavy many years ago.
when we were kids, we would ride our bicycles on top of the rails to see how far we could go
without falling off. it was never far. skinny rubber tires on steel rails were not meant for each other.
Frank
