Earlier you said it would leave Toronto at 4 AM. which at best is Kitchener at 5:30 AM. Why then would it have to leave Kitchener at 3:30 AM?The train would need to leave London at 6am, so the train would need to leave Kitchener at 3:30.
Either way, I'm sure there's little demand for trips westbound at that time. If people are travelling at that time, the 401 is empty, and it's infinitely quicker to drive - unlike the daytime.