The Department for Transport's analysis suggests that the costs of the bi-mode train, and the electric train followed by diesel loco-haulage, are around the same. The advantages of the bi-mode option are that it will not result in delay to passengers as a locomotive is being attached, that it will provide a more reliable service and that it does not require potentially expensive and disruptive infrastructure work at stations to facilitate the attaching of a locomotive.
Uni-directional seats (those not located around a bay-table) on the new Super Express Trains will have approximately (a) 750mm knee-room in standard class and (b) 915mm knee-room in first class. Similar seats on current Mark 4 carriages on the East Coast Main Line have approximately (a) 700mm knee-room in standard class and (b) 1010mm knee-room in first class.