Hi Liam1000,
Sorry to read that you have had computer problems, I think it might have been the route you were working on, (London Euston to Manchester Piccadilly) it's just far too long, with far too many junctions. I think the best computer in the world would struggle with the West Coast Mainline, even Virgin have problems running trains on it from time to time.
It's good to read your going to look at smaller routes instead, this is the best choice, little routes from here to there work best, and you can cram them with detail, so they give off a realistic and historical feel about them.
I usually build routes with steam in mind, then after I built the route, I would then be harsh in places and rip up bit's of track that I no longer needed, and leave the areas derelict with bits of old sleepers and old rusty rail in places and broken walls and bits of ballast and rubbish, just to give it that old fashioned route look, with a touch of modern railways.
Hope this helps, and good luck with your future routes, if you still have computer crashes from time to time, just check and see if you need extra memory in your pc, this sometimes fixes the little niggles and crashes.
Joe Airtime