This allows me to mention a few key points -
GO has to deal with identical rolling stock (different LOCO's mind you) and also has to plan some electrification around large heigh requirements. Remember pantographs are spring loaded poles and can be extended high enough to cope with height issues.
This brings us back to the main point, if need be Translink could expand the corridor or purchase trackage to secure more reliable service. To operate hourly service to Maple Ridge would require at most 2 trains? If Translink bought 2 low floor DMU's they could operate those as the hourly service and would see the benefits of the enhanced acceleration.
Quite frankly all considered I think in the future improving rail transit service to Maple Ridge by expanding WCE could be very economical. Buy track or double track, buy 2 dmu's (or emus if we REALLY want to electrify), and platform long shelters like is being done at virtually every major GO station and you'd have a very premium service that would be fully sheltered, could offer wifi, and would probably be able to attract significantly more ridership than the current setup, especially if travel times could be reduced.
http://www.gotransit.com/public/en/improve/projects/default.aspx