London currently has 2 Crossrails: Crossrail (Paddington/Liverpool Street) and Thameslink (St Pancras/London Bridge). However, there are 14 terminal stations, leaving us an entire 5 Crossrails short. I think every terminal should be paired with one on the opposite side of the city, with all trains rescheduled to run through to the other side. This may require massive disruption and tunnelling and hugely complicate the timetables, but it would be very funny.