In the summer it would be okay, 'cause the tank sure chills down. Free air conditioning. But bad in winter!
Seriously, compressed air locomotion has been used many times. Some mine locomotives used it. Problem is, the amount of energy you can store per pound of weight is quite limited. You've heard of cars that would not be able to pass up a gas station? Compressed air cars would be like that. You can store a mile or two of compressed air. You'd be recharging every couple of miles.
Only thing that would make it practical would be big breakthrough in tank material. Even carbon fiber tanks, or ones wound with music wire, cannot store enough.
If you DID come up with a tank that stored more energy, it would be VERY dangerous if it ever DID let go. Compressed air at very high pressures is VERY dangerous- more so than hydrogen. Look what happens when a 3000 psi tank ruptures. Now imagine what a 20,000 psi tank would do in a crash that ruptures the tank!