Comments by "Keit Hammleter" (@keithammleter3824) on "Steve Lehto" channel.

Steam engines came before internal combustion engines. But internal combustion engines rapidly drove steam out of the picture because internal combustion has about half the fuel combustion.
3
@jeffj2495 That's right - ships have used turbines. Turbines are efficient, but are not practical in such small sizes as required in a car. Turbines are good if you need thousands of horsepower. The various steam cars have had to use reciprocating engines, which have very poor efficiency. Most ships today though are diesel powered. Diesel engines are more compact than steam plant, giving more room for cargo or passengers.
2
@sandervanderkammen9230 Who is "they"? A typical gasoline car engine is about 25% efficient and coincidentally this means about 25 MPG. A reciprocating steam engine is about 10 to 125 efficient, therefore at best s steam car will get about 12 MPG. Check in any good textbook - look up terms like "Carnot Cycle", "Standard Air Cycle" which tell you the maximum efficiency that can be achieved.. As for steam vehicles being as usable as any modern car or truck, check the videos on YouTube posted by people that have restored old Stanley cars and Doble trucks that require a crew of two to drive. The British Sentinel steam engine road truck burns about 40 kg of coal per 20 km when unloaded. The calorific value of cola is about 2/3 that of gasoline, so if it used gasoline to heat the water, it would need 130 litres per 100 km. A similar weight truck (12 tonnes carrying capacity with a gasoline engine would need only about 35 litres per 100 km.
1
And be sure to watch all three videos Leno made on his Doble - so you find out just how much maintenance a steam engine needs, even when it has been restored by an expert team.
1