You ain't seen nothing yet: look at the [url=http://www.rossrail.co.uk/central/routeqn1.html]Amazing Routeing Question[/url].
The question is simple: what ticket should you buy to travel from London to Inverness ? The answer seems to be less simple: London to Carlisle.
Carlisle?
Well, yes. Valid routes for tickets are determined by something called the ATOC Routeing Guide. For every possible pair of stations this tells you what routes are valid. And it appears that a valid route from London to Carlisle is to start at King's Cross, ride up the ECML via Edinburgh and Aberdeen to Inverness, then back down via Aviemore and Stirling to pick up the WCML.
Feeling somewhat flummoxed, RossRail ticket expert Clive Feather wrote to ATOC. Here's his letter:
(For those not from the UK, Inverness is quite far north in Scotland, and Carlisle is about 200 miles south of it, across the border in England.)
I can at a pinch manage to navigate the Routeing Guide. Learning how to do so was useful for my job. I'm still always nervous when attempting to travel on something that should be valid but is unusual. It's all too easy for a ticket collector to be unaware of the specifics of the route you're trying to use, especially as they don't like you trying to save money by splitting a journey onto multiple tickets (which is legit but the train companies wish it wasn't!).
I was travelling to Penzance (southwest tip of England) last month, from Coventry (about in the middle), which is about a 7 hour trip. I wanted to meet my friend in London on the way there, but when returning go back via a more direct route. Any ticket Coventry -> Penzance is not valid via London (you can either go via Birmingham or via Reading), and if I bought Cov->London and London->Penzance as separate tickets, I'd have to travel via London on the way back. However, a friend of mine came up with an ingenious route, where I would buy Coventry->Leamington, Leamington->Bicester North and Bicester North->Penzance. The trick was that a Bicester North to Penzance ticket is valid either via London or not. The cunning thing was that no train in my plan would have passed through or stopped at Bicester North, but another rule allows anyone holding a Bicester North ticket to pass through Banbury instead, so all I had to do was make sure I was on something that stopped at Banbury.
I didn't do that plan in the end, as it turned out I didn't need to go to London after all, but it's a good example of how understanding the routeing guide is useful but incredibly hard!