I hold onto a suspicion that steam could still be useful in cars or trucks. The Stanley steamers could go over 100 mph and had great, smooth torque. Plus, the external combustion arrangement allows about 1/10th or better the pollutants. It might be more practical for trucks because a piston steam vehicle could be essentially direct drive, even with a clutch and tranny. The clutch wouldn't be needed in initial acceleration where a lot of the wear and tear comes on a clutch. A piston steam car starts from rest, with sufficient steam available. The clutch could be used to disengage from one gear to another. The Stanley had no tranny and a 1906 model still holds the
record for a steam car at 127 mph.
One often hears, or used to hear, people say, "well, if Bill Lear (inventor of the Lear Jet and the 8 track tape) couldn't make a steam car work, no one can." I don't buy it. Lear was an a$$ in the project from what I heard and I found someone who concurs with that at a steam enthusiasts web site:
Yes, the Lear turbine did work well, it was the rest of the powerplant that caused endless problems. They just tried too many high tech ideas out at the same time, had no time for real development and while the bus ran for a short time, the other components failed far too often. Coupled with Bill Lear's massive ego and yelling at everyone also getting in the way. His idea was that it was his money and he could dictate everything connected with the project. He didn't even know what he was looking at.
Also, as with the Monte Carlo sedan conversion, if it didn't work perfectly the first time, out it came and another whole idea was inserted.
First that silly Deltic engine, then staged screw expanders, then a gas turbine, then the Learium ( we called it DeLerium, a total fraud), and finally the turbine, which was supposed to use DeLearium as the working fluid; but wound up using plain water.
Lear's chief engineer in the beginnning was a fraud and a con artist of the highest caliber. He led them down the wrong path again and again until Lear fired him. Coupled with the basic problem that not one person at Lear Motors knew one damn thing about steam cars, nor did they want to be educated. It was engineering by decree. The whole thing was doomed to failure and it did, after they spent $17 million dollars.
From:
http://www.steamautomobile.com/ForuM/read.php?1,1424