I feel for the parents, but these kids are old enough to have been informed several times of the danger of walking on tracks. Play stupid games, win stupid prizes.
It's tempting to write it off as "kids being stupid". But we should not be lead into thinking we couldn't have done more.
I will admit to walking on tracks as a teenager, on low-speed CN tracks serving local auto plants. One time, I was even playing with a friend on a 50 foot high wooden trestle, hauling weird shit like bikes and barrels to throw it off the side. And we almost got caught up there, after about a half-hour, a train came sailing around a curve into our view. If we had forgot to look as frequently as we did, or if we mis-stepped between the ties bolting off of the trestle, we could have been killed or seriously injured (from the train and/or the fall)
We did it because we believed, from previous observation, that the trains ran slow. We were confident that if a train came, we'd had enough time to get out of the way, we even discussed it at length before doing it. We were invincible and smart teenagers. But we could have been wrong about the train speed, and we certainly didn't factor in the risk of snags or falls.
Side note: the sign waning "Danger: High Speed Trains" with a picture of an ICE 1 train did little to convince us, as that's not what we really saw. That's a lesson in effective signage.
I haven't been to a GO / Metrolinx school presentation, and it's been a long time since I went to an Op Lifesaver presentation. But I hope it factors this in, especially for the older kids. You think you know, but teenagers have a lot of brain development still going on, and risk-taking and analysis is still not fully developed I know I'm preaching to a lot of other parents and former teenagers here, but it's an important point to highlight: accidents happen, risk factors pile up. Cases like this serve as a good example of 'you think you know, but they didn't'. There's also the anti-authority element. But if we can do better to reinforce the real danger, there's a greater chance of kids *telling each other* to avoid the danger. Another 15 year old saying "Bruh, that's crazy, stick to the side" is likely going to work better than a guy in a shiny vest saying anything in a school gym.
Anyway, stepping off the soapbox here, I am curious how Metrolinx responds, and if that means better fencing along rights of way.