rbt
Senior Member
Metrolinx will not be having the big diesel locomotives stopping at the new RER stops, whoever told you that is misinformed. They won't even fit as the platforms won't be long enough for 12-car bi-levels.
Some parts of RER will be 12-car trains. GO is expecting to order 3 or 4-car consists which can be joined together to form 6/8 and 12-car length trains where necessary. Some lines, like Lake Shore West, will need the 12-car capacity with RER as they already unload a 12-car train at Union station every 6 minutes during AM Peak (express + local).
Going to 6-car single-level trains on Lake Shore West would require 2 minute combined express/local frequencies during AM peak at Union just to support today's ridership without shifting the time they ride at.
The new stations aren't on Lake Shore West and will be sized to the expected ridership of the line; but that's not really related to RER or electrification.