Dan -
If you do a "created by" search on the name timberdv, you will find a route for Trainz 2004 from Chicago to Des Plaines (the old C&NW Northwest commuter line). It has variations that use Magicland's green bi-level cars as well as Amtrak cars. (Unfortunately, I do not believe the bi-level cars are available anymore, which is too bad.) The routes have rather odd names:
-C&NW 2 Track Amtrack
-C&NW Amtrac
-C&NW Bi-Leval GReen
They are all the same route, just configured a bit differently depending on installed rolling stock. Someone else may have to help you with installation, however, depending on the version of Trainz you have. The Amtrak one once worked for me on Trainz 2006, but I have a new PC and am about to install a newly-purchased copy of Trainz 2010.
Hope this helps a bit--I'm a fellow C&NW lover myself!
Ken