Ok, so could they have built unpowered cars instead of powered ones?
Correct. The critical factor in the early days was climbing capacity. I spoke to a Bombardier engineer in 2004 during a V Locity open day at SCS. He said that in a three car set, an unpowered middle trailer car would be ok for Geelong or Traralgon, but not Ballarat or Bendigo as the gradients would be a problem. But when you have one trailer and three
powered cars, as suggested by Kuldalai, this is less of an issue. So 4 car sets of this type could be an option. The trailer cars are 1/2 the price of a powered car and faster to build. The Alstrom factory in Ballarat could do it, to take the pressure off the Bombardier Dandenong factory.
Also the next generation of long haul DMU’s can be build to a higher powered horsepower. Eg WA Prospector. So you could build a 5 car set, with 3 powered cars - Powered - trailer - powered - trailer - powered. It could do the 130 kph over all the routes, and more on the RFR sections. The hp for a V Locity car is 750hp. But this can be increased to 1000hp per car. Keep in mind that a powered car weighs in at 68 tons, but a trailer is 40 tons.
So for example:
5 X powered cars is 68 tons X 5 = 340 tons. 750hp x 5 = 3750hp
My suggestion weighs (68t x3) + (40t x2) = 384 tons and 1000hp x 3 = 3000hp.
Yes the all powered train has a slightly better power to weight ratio, but not so much as to be impractical.