Originally Posted by BCPhil
That's what I'm getting at. We need new cars now, and especially when Evergreen opens, so we need to buy something in the near future. And further into the future, 4 car (2+2) MKII trains will not be long enough to handle demand. So our options are to either maximize space utilization and use 5 car trains, which will require a new type of car (C car). Without that we will have to expand platforms to handle 6 car trains (2+2+2)....
The other option that you don't mention is to allow the system to become overcrowded due to continued use of 4 car (2+2) MKII trains (without platform extensions), and then purchasing 5 car (3 + 2) trains in the future.
That's the trade-off - (1) maximizing efficiency (with a concurrent domino effect adding costs for on software upgrades for new train lengths, etc. and new/expanded maintenance facilities) or (2) control current expenditures (buying A+B trains with no concurrent domino effect) and deal with capcity issues later.
In the long term, when Evergreen and the UBC extensions are built, that route could still use 4 car (2+2) MKII trains since it wouldn't be as busy at the Expo Line.
BTW - I don't think the Evergereen will have a new maintenance facility - just a storage yard.