Rolling stock is not the issue. GO has yards full of idle equipment during off peak hours.
Up until now, none of GO's lines other than Lakeshore have had two-way capability.....since the 1950's and beyond, they were mostly single track. Signalling systems only arrived in the last decade in places, and sidings weren't spaced to support GO. GO is finally getting enough passing capability to run two-way service.
GO simply hasn't been on the ball in getting this going in an organized way. One valid excuse has been the extra rapid addition of so many peak service trains, which has gobbled up all the new crews as fast as GO/BBD could hire them. Even so, I question whether hiring was jumped on well enough or aggressively enough. For instance, the service plan for GTS post-UPE was documented in 2010 and didn't change between then and UPE's opening.....but GO didn't have enough crews ready when UPE opened.....that's five years' lead time.
Each route has had some logistical or infrastructure issue that holds up the whole line - another example is the makeshift station at Etobicoke North, which despite the huge expenditure on GTS can't support 2-way at rush hour.
It has been excruciating watching GO fill in the pieces one at a time. The good news is, we are finally close to having these services. That's a real step forwards.
- Paul