IIRC basic thermodynamics shows that ordinary steam engines can't be very efficient. So, don't get good MPG or miles per bucket of coal, or whatever fuel.

IIRC the main reason for diesel-electric locomotives for trains and large ships was that it was significantly more efficient than just steam, at least steam with just a boiler and pistons.

Of course, really large ships generate steam and then run it through a steam turbine -- no Diesel around.

> no cooling system.

How can this be true?

The acceleration is more of a function of the powertrain design in steam cars. If you replace the direct drive drive train with one similar to a ICE car (ie clutch+transmission) you can get the acceleration of a ICE car in a steam car. If you want to keep the direct drive though you would need to have a larger engine and use hook-up and variable cut-off to keep the efficiency of the smaller engine while cruising. Steam engines on the whole are pretty similar to electric motors though in having most or all of your torque from 0 rpm which is why many steam cars were direct drive (I think only the Whites and a few race cars had a conventional layout instead of direct drive).

Stirling engines have many of the advantages of steam, many of the disadvantages, but they lack the disadvantage of high pressure containment. It's likely that power density would have been too low, however.