Thanks for this fine info. After viewing the Railbike site, I thought of another vehicle which I believe was called a RailRodder. It was used by linemen for traveling the rails between grade crossings when performing light line work or by track maintenance personnel. This unit preceeded the HyRailer of today. These vehicles consisted of 4 semi-pneumatic, tired wheels to which flanges made from flat plate steel were bolted to these wheels. The two front wheels were mounted to a free-wheeling axle that spanned the trackage rails. The two wheels on the rear were similar but were keyed to the axle which was driven by a belted pulley driven by a small Briggs & Stratton engine. This engine was mounted to a lightweight square-tubular frame that held the riders seat that was mounted directly behind the engine. Also a tool tray for lineman tools and supplies was mounted to the frame The tubular frame was able to be easily broken apart for ease of handling and transport from a truck vehicle to point of assembly and point for use on the track. There was a foot pedal which operated a take-up pulley for the drive belt that governed speed.
This vehicle was originally built at Perry, OK but I believe was later sold to a business in the Eastern US.
Do you or anyone know if this unit is still available and where parts may be obtained?