I am not a train expert but I offer this. The steam locomotive was essentially a primitve boiler design that had certain constraints and it was I beleive a combination of things including air pollution factors that eventually phased it out. The calorific conversion rates from other more advanced furnace designs in other applications using coal was/is much higher. So the poor old Puffing Billy was way down in energy conversion. If however instead of using coal to fire the boilers which creates a lot of air pollution, they used a different fuel such a LPG, (or indeed diesel) the story could be turned around tomorrow.
Same sort or combination of reasons why some rails system use pure electric locos-clean air, efficiency.
The diesel/electric is a very inefficient machine. It has many merrits but fuel efficency isn't one of them.
New technology for steam use means using what they call "superheated steam" and multistage energy recovery based on the principles of latent heat. In advance designs they use steam which is condensed and recycled so it doesn't go to waste and you dont need to park next to a fire hydrant every 2 kilometers
Anyhow, the point I was orignally trying to make is that too often we fail to learn from history casting aside too easily the lessons of the past trying to build better outcomes for the future when some of the answers are starring you in the face.
Don't forget, even the most sophisticated nuclear power station still uses steam to make the electricity you are using in your PC to read this text on so don't sell steam too short.
One could stretch the bounds of credibility and say your PC is actually running on steam (roundabout)
Ever notice how political outcomes are rarely logical ones and yet societies around the world live by them all the time?
OK, I have had my gripe and I know this is not a political forum but a wondeful car forum so I will make like a turtle and pull my head in and get back to the core issues usually discussed here.
) with a response! (Not that it is THAT an important a thread, but still...)