Judging by their business case as well as previous statements, it's 99% going to be EMU/Electrification unless they decide to change their mind last minute.This is one of the many problems with how Metrolinx has proceeded with RER. It is patently ridiculous that 6 years after RER was announced they still don't even know what kind of trains or technology they are going to be using. Now this discussion about catenary on the Kitchener Line which may not even be relevant if they go with battery or hydrogen. They are rebuilding stations and expanding/widening the rail network without putting up the catenary at the same time because again they don't know if they will be needed. That means if they go catenary all the disruption will start all over again.
It is the most ass backwards way to proceed with transit known to man and all because ML refuses to make any decisions about anything at all. As for this stupid notion of waiting for the bidders, that is not only a cop-out but one that will not serve Torontonians. Having a system that's based upon strictly the financial operation dictated by companies is offensive because what is best for a company does not mean it is the best system for the travelling public.
Can you imagine building the Eglinton Crosstown and then at the last minute deciding what king of trains and technology they have decided to use? It is patently absurd. Every other system on the planet has the trains and technology decided BEFORE it goes out to tender so they get more competing bids, can have more proactive, effciient, and coordinated corridor and station planning, and the travelling public actually knows what they are going to be getting. This is why the much shorter OL is getting all the attention but isn't nearly as transformative as RER.............it doesn't mean anything to anybody because nobody knows what it is, including ML.