@Kalimakhus
So true about the loop problem. I'll try to follow Better AI, Revolution and BUG mods' forum sections in case similar problems are described in their bug threads. It's bit annoying that it takes this long to get tracked down but I'm sure it will eventually get fixed. While modding RoM I'll keep my eyes open for any oddities in xml files - one thing that I just realised was that random events can be the cause too and random events can also crash the game without any error messages so need to run couple tests with events disabled. I also know that jdog changed Better AI's handling of random events when new civs are made during game - was one of the bugs I had found from earlier revolution version.
I like the new routes too and seems AI really wants to rush to techs that allow new route types.

Paved road requiring stone resource gives strategical advantage if you have access to the resource - and Electric Railroad allows player to build railroads bit later if he lacks the oil/coal resources which are needed for regular railroad.