Dallas was a city of moles, back before electric subways Dallas had an underground rail system, steam powered
It ran under downtown and was used for cargo not commuters. The engine was a pre-charged steam driven locomotive, i.e. no onboard combustion due to fumes
The engine would stop above ground at a boiler/recharge station to get pumped up before each run.
Now the wild part of the legend depending on which one of a hundred different stories you want to believe, is that the engine is alleged to still be down there, walled off in a section of the rail tunnel. Former UER and DEA member Barry Kooda and I researched this urban legend extensively. Facts and fiction seem to run parallel with half truths and here say. He did find a walled of section with tracks running under the wall that was no doubt where the little engine that could, did. Seems he forgot his blasting caps that day and now the building is inaccessible so we may never know whats really behind that wall. Maybe theres others, the whole route is walled up, made into parking garages or excavated for the new(ish) American Airlines arena.
Believe me we tried. At one point we assumed (wrongly) there could be an intersection with the now underground Mill Creek. (see The Rat Race Drain) http://www.uer.ca/...ow.asp?locid=26035
and there are tunnels built that exceed the height of any reasonable storm drain and an obvious RR crossing but none of it lined up with the supposed route from the AA arena to the old business district.
I imagine the quest and theory machine goes on, somewhere I have not researched this in about 10years. I really miss those days and those guys (DEA) but we have all moved off or moved on. The next generation of the Dallas Explorers Association will need to carry the torch now.