Unless there's leaves on the line, snow on the line, workpersons on the line, cows on the line, broken down trains on the line etc. In which case they'll decant the passengers onto buses. Anyway, of those poor souls who have no option but to go to Birmingham - who exactly wants to get there 30 minutes quicker? Any train outta London is a good one in my book and I was always just glad to "Leave the Capital" at any speed with The Fall ringing in my Walkman headphones.
Anyone who's been to Edinburgh over the last few years will have seen what these massive white elephant "public" works can do in terms of destruction, massive costs and inconvenience for a pitiful return. Auld Reekie council taxpayers got half a single tram route and a One Billion Pound bill. Scotland could have dual-carraigewayed the entire A9 for that and still had change for chips and a perfectly good Edinburgh Bus home for everyone.