...........................I haven't yet explored Open Rails, but I do wonder how much of a challenge it is to get an operable setup. It's all moot to me though, as I can't find my MSTS disks to reload it on my latest computer!
You don't have to have MSTS installed to be able to setup a fully working Open Rails system. Peter Newell has done a lot of pioneering work. Peter and I made a couple of short 'demo' routes to test OR as a 'stand-alone' system - Craven Timber Railway and Manning River Breakwall Railway. As far as more expansive routes go, we were able to run Tweed Railway V2 quite successfully under OR - see here:http://www.tweed.coalstonewcastle.com.au/route/route-install/
Once you've got it all working OK, you can expand on that and add additional stock and/or routes to suit - see notes under 'expanding your world'.
A bloke in Wollongong has successfully loaded and run just about all of the current NSWGR steam era routes in OR without major drama, just a few tweaks needed here and there.
The latest OR is version 0.9 only released recently.
Have a go at it, you might be quite surprised at how good it is. OR doesn't have an editor yet, so you can't build new routes (currently we're using MSTS RE to do that), and new stock can be built using the old stalwart TSM.
Regards, Brian Bere-Streeter