One issue with steam engines for vehicles is the time (and fuel use) to get the boiler up to working pressure.
http://www.sdrm.org/faqs/hostling.html
The bigger the steam engine, the longer it takes to get started. All those tons of water have to go from "cold" to "hotter than just boiling in a tea kettle" after all. And all of that energy -- fuel -- is "wasted" as far as liters-per-100-km are concerned. In the article above, the engineer uses 45 gallons of kerosene ... 170 liters ... over six hours or so, before moving the locomotive an inch.
A steam ship takes, generically, about a day to get the boilers up to full pressure. There are some ways to speed up the process, but they're not going to be easily applied to an existing, old steam locomotive.
Railways had crew (hostlers) in the roundhouses, back in the day, whose job was to keep the boilers hot.
Steam engines are not really more "reliable" than diesel engines or turbines of the same size/power; they can be very reliable, but need a lot more tending, lubrication, and maintenance to achieve that, compared to a large diesel engine.
Of course, for an engine in continuous operation -- e.g., a municipal power plant -- the need to 'restart' isn't present.
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Michael B.