rh77 - good train post. the house is not far from a shunting yard, and i used to cross the tracks (illegally - but never got busted.. or busted up) when i worked at a nortel factory on the other side of the tracks.
the yard engines are icons of corporate wastefulness: they NEVER turn them off, from november through march. they idle continuously all winter. i suppose they're hard to start when cold, but thats' ridiculous.
as for why GM doesn't apply their train know-how to road vehicles? they actually are:
Ten GM Diesel Hybrid Buses to Oahu
http://www.greencarcongress.com/2004..._diesel_h.html
gm's hybrid strategy is interesting to say the least: focusing on the most "wasteful" vehicles first. there is some logic in it (more fuel is saved by improving a bus' mpg from 4 to 5 mpg, than a subcompacts' mpg from 40 to 50.) but it's not helping their green image.