But since it makes you sound like a BRT advocate, first, I'll say that there's nothing 21st-century-ish about your suggestion. Nor would any mass transit agencies pick up on it, since it's so impractical and most likely very, very expensive to implement.

There are already diesel LRVs in existence—one example is the O-Train in Ottawa, Canada, which uses freight tracks, but with "time-share" between freight trains (neither can operate on the same tracks at the same time of day). Another is slated to open soon in southwestern New Jersey, the Southern NJ LRT line between Camden and Trenton in that state.

If you want to be more flexible and be compatible with the FRA, there are plenty of DMUs available, with FRA-compatible versions available from Colorado Railcar ( http://www.coloradorailcar.com ), both single-deck and double-deck. Either that or if these ROWs you speak of are actually disused and no freights use them, then they could be re-classified as FTA-regulated railways for diesel LRT usage, so long as they are henceforth separated from any connections to active freight tracks.

Either that...or, if you think that your buses truly obey the "economies of scale" rule (they don't—their short lifespans dictate that only too well), how about your city take over the ROWs and pave over them, turning them into busways. Now, that'll be way more expensive than rehabbing them and using DLRVs on them...but hey, I'm only one guy speaking MHO...

[This message has been edited by irishchieftain (edited 09-02-2002).]

True "light rail" is what used to be called streetcars. Can you mix streetcars with regular rail? Yes, it has been done several times in the past in this country. But, on new systems you usually would not want to because one would lose the advantage of light rail - cheaper to build. Light rail is 'light' because it doesn't weigh as much as regular trains and is smaller. Lighter weight means bridges and track structure can be built for less money. Smaller means that clearances for tunnels and bridges are less, again saving money. True light rail bridges and track structure probably would not support regular trains and the clearances would be too small. But, where light rail uses old or existing rights-of-way, in theory, heavy rail could use the same track. Would it want to? Most likely not because the freight railroad already has mostly given up service on the line anyway for it to be willing to sell or share the right-of-way for light rail use."

First, the devices to put busses on rails have been around a long time. It would be much the same as used for various pieces of hi-rail work equipment.

Second, any track unsuitable for freight trains for reasons other than bridge weight restrictions and clearances would be highly unsuitable for passenger service. Generally, out of service railways have trailed out their last years with little or no maintenance and give a rough ride at 10 to 25 mph. This will never work in passenger service, where speed is virtually everything.

third, there is precious little if anything to be saved by building a track for light rail instead of freight. The grades can be steeper and the structures may be constructed for a lighter load, but a structure for a 15 ton maximum axle is probably more like 80 to 90% of the cost of a structure built for a 40 ton axle, not 50% of the cost.