I've found frame rates in Trainz 2010 a bit jarry at times, but I put this down to my graphics card, I have a Nvidia Geforce 7300, However I am in the process of upgrading to a Nvidia Geforce GTS250, this should solve my problem.
The point I'm making is, if you have a decent computer with a good graphics card, then I would suggest you upgrade to Trainz 2010, it has a superb UK route called the East Coast Mainline, it's set in the 80's, and your test is to drive the HST 125 from York, calling at various stations along the way, including Doncaster, right the way through to Kings Cross London.
There are also other superb and very well detailed routes from various parts of the world, there is more content and better looking content, except for the HST coaches.
Speedtree is a new item in Trainz, some people like them, some don't, if you don't like them there are other free sites to get trees from including Greenier and Jankvis trees, Some of Jankvis trees are included in Trainz 2010 under the name JVC, these are superb alternatives to speedtree.
As for the steam issue, I can't help you with that as I'm a diesel / Electric locomotive fan (Unless it's GWR Steam :udrool:castles:udrool:GWR:udrool:city of truro:udrool::udrool::mop: sorry about the drool, this is the main reason I don't talk about GWR on here)
Hope this helps
Joe Airtime