I just saw an SUV on the road that appeared to have a set of metal railcar wheels in addition to the standard tires. The metal wheels were raised a few inches off the ground, and didn’t appear to have driveshafts connected. The vehicle had a railroad company logo on the door (Norfolk something). Was it really a dual-use rail/road vehicle? Are the metal wheels load-bearing, or just guide wheels? And what do they use this vehicle for?
Google “‘road rail’ vehicle” and you’ll get plenty of results: this, this and http://www.railway-technology.com/contractors/track/imagemap/imagemap3.html]this give some of the uses.
Yeah, I did the same search as GorillaMan.
It seems that the “rail wheels” have their own independent (hydraulic?) drive system. They are capable of driving the vehicle and they raise it so that the conventional wheels are off the ground.
If someone finds a good link describing how these systems work I’d be interested in seeing it.
They’re often used for track inspections. I’ve usually heard them called “hi-railers”, if you want a term to search on.
I found a description of how the system works on this page:
The railroads used to (and probably still do) use small cars called “speeders” that would only work on the tracks, but they seem to have been mostly replaced by the dual-purpose hi-railers.
Thanks for the info, I had no idea they were so common. I guess it would have looked natural to me at a freight terminal, but it sure seemed strange to run into one at a McDonald’s parking lot.