At first glance, this is excellent news and shows that the Toronto Area might just be starting to catch up with the more enlightened parts of the world. Indeed, there is much to be praised in this decision: the work required to boost capacity must not be underestimated; the cost of additional crews and the increased maintenance costs due to increased wear and tear are important.
However, consider that GO Transit currently operates seven rail corridors - yet this announcement only affects two of them. Yes, they are the busiest and most densely-populated routes, but GO risks a sort of post-code lottery. Consider the Richmond Hill line, standing-room only with few trains at rush hours and no service during the day (despite much of the Bala sub being empty). I hope that service improvements will slowly be made to the rest of the GO network.
I have very different views on this decision when I see it from the perspective of northern Ontario. While the Northlander was deemed surplus to requirement, residents in the Toronto Area are being told that they no longer need to follow timetables because increased frequency will make their journeys convenient. In northern Ontario, much of the rhythm of life was dictated by the one Northlander train running six days a week. The north-south divide is clear.
GO trains to run every 30 minutes all day on Lakeshore lines | Toronto Star