Back to the subject of HFR alignment, I'm really curious what they plan to do around Peterborough.
I think building a Peterborough bypass is important to the project's success. It won't be cheap, but I think the status quo of routing the line along the Havelock sub through downtown Peterborough will cost tremendous amounts of travel time. It's not just the mandatory stop, but also the fact that the line trundles through a lot of residential neighbourhoods and has many grade crossings at funny angles. Having a mandatory stop will be particularly useless for people traveling westbound from Montreal to Toronto. The number of people who want to disembark in Peterborough from Montreal on any given train can probably be counted on one hand, and it doesn't make sense to have empty seats for 80% of the ride just to pick up the large number of Peterborough riders heading to Toronto.
Here are two significant roadblocks that have to be addressed at the very least with the existing line:
This crossing, at the very least, will have to be grade separated. It's a busy commercial stroad and the crossing is at a weird angle with a busy T-intersection just a few meters away.
This swing bridge over the Trent-Severn waterway is 120 years old and in need of replacement. During the summer months, it's permanently open because of the volume of boat traffic. This will have to be replaced with a high clearance bridge, otherwise trains won't be able to keep a schedule.
My preference would be for a Peterborough bypass that roughly travels along the median of Highway 7 south of the city with a park and ride station roughly
here.
Apart from ROW agreements/acquisition, I don't think it will be much more expensive than routing the line through town, and will have better long term benefits. Having a greenfield station also allows for multiple tracks/platforms, allowing for local Peterborough-Toronto service which is really where the vast majority of Peterborough passengers are heading to.