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General discussion about locomotives, rolling stock, and equipment

Moderator: John_Perkowski

 #226594  by JohnCeglarek
 
I've got a question regarding trucks that can operate on both roads and railroads. When these vehicles are on the railroad tracks, are the wheels driven by the engine directly (or through a transmission) or do these vehicles have traction motors and a generator like a locomotive?

Thanks,

John
Last edited by JohnCeglarek on Mon Mar 20, 2006 2:50 pm, edited 1 time in total.
 #226598  by octr202
 
JohnCeglarek wrote:I've got a question regarding trucks that can operate on both roads and railroads. When these vehicles are on the railroad tracks, are the wheels driven by the engine directly (or through a transmission) or do these vehicles have traction motors and a generator like a locomotive?

Thanks,

John
Almost always through the vehicle's existing drivetrain. A hi-rail pickup, for example, usually is propelled by having the trucks rubber tires rest on the rail. Thus, the rear wheels provide propulsion while on the track. The rail wheels are there to, well, keep the vehicle on the track.

 #248448  by vector_one75
 
Back in the 1960's, the Red Arrow Lines in the Philadelphia western suburbs applied this principle to one of their buses. While they were probably looking to reduce streetcar trackage, one could also argue that the same vehicle could extend passengers' "no-transfer" service to self-feeder bus routes connecting to rail routes by simply hopping the bus onto rail tracks. In that positive context it was a great idea.

Why it never went further than just an experiment I imagine was that winter snows in any northeastern city would not function well with rubber bus tires propelling the vehicle on steel rails. Perhaps the additional training and control procedures for bus drivers on rail lines, and maybe a labor union demarcation problem too, and probably little or few funds available to do more research and development of the propulsion technology to overcome the snow problem is why a good idea to expand use of the rail system by self-feeding buses on rail lines never really took off.

One incident of poor traction in snow in a trial can destroy any project once the media have a go at the "failure", and the public will never accept anything that does not have the media's blessing as a "works in progress" even if part of the effort to perfect something may require a hiccup in the process. It was good that when Thomas Edison was developing the electric light bulb he didn't hire a PR consultant until after he had it perfected in secret. Once asked by an assistant whether there was any point continuing in so many tries that didn't work, his response was that he now knew 1001 etc ways one should not try it, and each one more "failure" brings us closer to the true answer as to how it SHOULD be done.

Sincerely,
Vytautas B. Radzivanas
Perth, Western Australia

 #253418  by trainiac
 
Almost always through the vehicle's existing drivetrain. A hi-rail pickup, for example, usually is propelled by having the trucks rubber tires rest on the rail. Thus, the rear wheels provide propulsion while on the track. The rail wheels are there to, well, keep the vehicle on the track.
One thing I have noticed that proves this point is that the larger hi-rail pickups I've seen (such as a Chevy Silverado) are modified with tires that are more closely spaced than normal--specifically to match the track. Kind of gives them a "top-heavy" look.
 #265035  by Rockin' Roller
 
Most pickups do have different offset wheels to line up the tires on the rails. They also have tires that require 90 psi. of air in them. They are rough riding on the highway.