Where do you get the info that all the rolling stock will be dual-pickup? I was under the impression it would be mixed with some light-rail to access Wirral and Liverpool Waters.
There has always been a desire to get Wrexham Trains (run by Arriva Wales) into the central Liverpool underground section. But a dual-fuel electric/diesel with tanks of diesel in a tunnel precluded that. I see no problem if the fuel tanks are made to nuclear fuel container specifications - crash proof. Having a number of trains made to this specification must be far cheaper than electrifying 27 miles of track. A section of electrified track can be at stations to improve acceleration. Much cheaper and using bio-fuel is an eco advantage.
If such trains are within regs and are ever built, then they would extend Merseyrail onto Wigan via Kirby, to Helsby, etc. The Merseyrail Outer Loop could be reinstated with electrifying it - far cheaper.
Not all out of the gate but it was mentioned in one of the procurement documents they will have provision to add pantographs if needed. It's not too difficult with modern EMUs AFAIK.
The light rail at Wirral waters is a separate thing all together a street car system with interchange to rail. and the Liverpool scheme is not even on the drawing board, the other light rail in the area Mersey tram collapsed years ago.
The loop tunnel means EMUs are the only sensible option unless we have really awkward passenger flows at James street and two changes to reach northern and city lines.
