The GO site is usually good for delays, although not always with reasons.
I was taking a midday train home to Bramalea last week, and it stopped just pulling out of Malton for about ten minutes. After seven minutes, I hopped onto the website, and the only explanation was "Delay: Stopped". A minute later, the customer service ambassador said something, but no information on why we were delayed - long enough to miss connecting Brampton Transit buses.
A few weeks ago, they were running a reduced winter service because of the weather. The site said as much, but did not show a schedule. I get to the station, and there is a 1:30 gap between trains instead of the 1 hour gap. I understand weather is hardly their fault, but such a different schedule was not clearly communicated.
And a third story that just happened on Friday. A good majority of the platforms at Union (5-11) were blocked off, the doors from both Bay Teamways closed. I don't know why, nor was there any announcement of why. So I get to my usual waiting at the west teamway, and see this, so there's plenty of time, so I switch over to the east teamway, and it's blocked off there too. Now the platform comes up for the midday Mount Pleasant train, and it's all the way over on platform 24, which is vastly different from normal, and also quite a trek away from its usual place. Blocking platforms off, even if only sparingly used midday without explaining why or for how long is not good.