This is a good idea and would be particularly useful as more routes become available. Even better if the choice could be made in the route selection window in the game itself so that it fitted in with the general design of the opening screens.Because it's very easy to install a large number of routes, it would also be nice to have some sort of folder facility (similar to Windows Explorer) so that you could have, for example, folders for Narrow Gauge, British Steam, British Diesel, German, or whatever you wish to let you organise your routes.
Note that it is relatively easy to re-order your routes now but it does involve careful cutting of the relevant sections of the routes.xml file and pasting back to where you want the route to be in the listing. Not as good as a built in facility but stll quite practical. As usual, always make back ups before tinkering with files.

