E400's? They must be absolute bonkers! All the ISBE 6.7 litre engine is designed for is the typical 38, 39, 40, 62 and 63 run through Newcastle, not a 20 mile endurance route consisting of high speed dual carriageways and rural roads. Mind you though, there's nothing else much better around particularly since the B9TL was replaced by a smaller and less powerful and suited to purpose B5TL. The only way Arriva could pull off a successful and reliable series of route upgrades across Northumberland would be to negotiate 37 Gemini 3's with the B8TL engine for use on the X10, X11, X15, X18, X21 and X22.