I've seen someone say that elsewhere although I doubt it will happen for a couple of reasons.
- There doesn't seem to be any plans by SETS to re-activate the 2 U set motor cars, they are concentrating on their electric locos. It was just announced that the project to re-activate 8649 will begin any day now (they said late May on their web site). The next project will probably be 4615.
- I'm not sure if 2 U boat motor cars would have the required power to haul the AK Cars
- I'm not sure if the U boat motor cars or AK cars would fit through the metro tunnels or clear the platforms. How wide are the metro trains? The u sets are about 2.95m wide
- I doubt the U sets would be able to couple with the Metro trains in any way.
- Not sure if any other rolling stock or locos would be able to fit the metro line, including the surviving electric locos such as the 86 class. Not sure how they handle maintenance on the Metro line, but no doubt something like some operational 86's, given the extensive tunnels (including for the future stages of the system) would be handy.
For the record, the 4 86's which were re-activated in late 2004 for the Bondi Junction works were used in push-pull config to haul the AK cars underground - one at either end.