Will the bi mode have HST style powercars?
The original DfT IEP specification and subsequent Hitachi SET proposal had the power sources in the end driving cars.
All the intermediate vehicles were either traction motor fitted, or un-powered trailer coaches and would take their power from a power bus, irrespective of what type of traction was fitted at either end.
The bulk of the fleet was to be 10 cars long, with less than a third being 5 car long.
There were two types of driving "power cars"' one electric with pantograph and transformer equipment, the other with a diesel engine and electric generator equipment. Neither type had any traction motors in order to save weight.
The diesel powerplant was to use Hybrid technology, as demonstrated on the Hyabusa HST test-bed, using rechargeable batteries to boost power and lower fuel consumption and emissions by a target figure of 15%+
The idea was that any combination of "power cars" could be fitted at the ends and could be changed (in several hours) to suit the routes on which the SET was deployed.
The proposed configurations were....
All diesel - two diesel generator driving vehicles
All electric - two electric pantograph driving vehicles
Bi-Mode - one of each type of driving vehicle
An all diesel could be turned into a Bi-Mode or an all electric, simply by changing the "power cars". Similarly the Bi-Mode could be made all electric or all diesel, just by changing one end..
The idea was that this would also suit a rolling electrification programme as well as provide fleet deployment flexibility over the service life of the type.
The all diesel version was subsequently dropped for various reasons.
As a straight comparison, this version should have been able to trounce an HST on several fronts (acceleration, passenger capacity, fuel consumption, emissions, modern electrics and electronic services etc), however the powers that be decreed that an all diesel variant was undesirable and would not be required?
As we know, that's all gone out of the window now and the IEP specification and Agility trains response to it has gone all over the place. it seems to be a total mess now.
There may be certain merits in using underfloor diesel engines as opposed to larger units in separate power generator vehicles, but unless someone can enlighten me, I believe there's a much better solution in the original design.
Plus the opportunity to utilise the Hybrid diesel powerplant has been lost along the way.
One of the objections to the original plan, was that the Bi-Mode would be underpowered off the wires. Surely the capability of this combo could have been boosted in some way? e.g. electric panto/transformer kit with two diesel generator vehicles, either combined in the same vehicle or in a passenger vehicle?
Anyway, while everybody complains and bickers about the power sources and the Bi-Mode (electro-diesel) aspects; very little attention seems to be given to the fact the Treasury and DfT bean-counters have managed to sneak-in a reduction in passenger capacity for these new trains.
Where the bulk of the original fleet were meant to be 10 car trains, they've changed that to the bulk being 5 car trains, with the longer ones being only 8 and 9 car. IMHO, that's a far bigger issue; after all one of the key objectives of this order was to enhance capacity on our already crowded network.
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