I've suggested it before for Train Simulator but I think that, in some ways, would be better suited to Train Sim World. My Train Simulator proposal is linked here.
What's going to happen is something like this to DTG needs to ask the provincial government of Ontario to use GO Transit in their game. If made Richmond Hill line will give Oakville division passenger trains. However Amtrak/VIA Rail Services on Oakville subdivision requires Maple Leaf route
Rolling stock for the route should be exactly the same as Caltrain with Baby Bullet getting a reskin.