Not in their interests
According to Network Rail, the 3-trains-per-hour Virgin timetable to Manchester and Birmingham reduces capacity on the West Coast Main Line.
Why have Virgin not requested the Office and Rail and Road to look at recasting the timetable, to allow 4 trains each hour to Manchester and Birmingham?
According to Network Rail, the 3 trains per hour timetable ‘maximises revenue’. In other words, it is not in the interests of Virgin Trains to run 4 trains, because net income would fall.