Plans to change HS2 train size could reduce capacity and speed in north, says expert

Review of original train order is meant to prevent service problems north of Birmingham, but it may do the opposite

Plans to change the size of HS2 trains to maximise capacity are likely to inflate costs and mean fewer seats and slower services north of Birmingham, a senior government and rail industry figure has warned.

The £2bn order for 54 high-speed trains, to be built in Britain by a joint venture of Alstom and Hitachi, is under review as HS2 Ltd seeks to cut costs and renegotiate contracts.