The issue of turbine trains comes up in this forum about, what, twice a year?
And it's a rehashing of the exact same script every time. Nobody learns anything from the other side.
So I guess I'll go ahead and play the part of the pro-turbo side since it's been missing here so far:
Modern turbine engines in trains actually are a good idea that has never been really tried. Turbines are highly efficient, light-weight, low maintenance, and based on now-mature, now-available technology. Yes, they are only efficient when run at efficient speeds, so run them at efficient speeds. It's not fair to call them fuel hogs because they can be run in fuel-hogging ways.
Turbine-powered trains did poorly in the past, yes, but turbine technology has progressed by leaps and bounds since then. With advances in material science, computer modeling, better understandings of viscous flow, and other technological aspects, the turbo technology of today is generations ahead of where it was last time turbo trains were given a real chance. Should we judge modern diesel engines by those at the turn of the century? Hell, advances in turbo technology are even used to improve modern diesel engines!
So go check out the publications surrounding the Jet Train. And then remember that we're a decade advanced from even that!
But don't think all of the anti-turbo guys in this forum are presenting the whole picture. It's not nearly such a closed case. I work with turbo technology every day, and it's just astounding to think how much things have advanced in the past ten or twenty years.