A brief venture in to the US rail thread, as they usually descend in to quasi-anarchy, and a few points:
- Private passenger rail is doomed, the only way is state/federal backed passenger operations.
- Widespread passenger rail is only really viable in this very rough area of the US, as well as California. And by viable, I mean a rail network, not just one or two routes which might be viable elsewhere.
- You need freight and passenger operators to respect each other and work towards a common goal. Freight operators can earn some reasonable extra revenue through track charges on lighter used routes, especially if they are principally only used at rush hour.
- And on the back of above, you need them to work together towards keeping routes going, especially with double track for two-way operation. If the freight operator wants to single track an important passenger route; the passenger operator can buy the second track, and then both sides operate the route as a two way railway maintained to Class 4 or something. Share costs.
- Electrify routes to reduce operating costs (with high level overhead lines to not interfere with double-stack freight), operate multiple units with fast turn around times to make better use of rolling stock.
You'll end up with a load of city-based urban rail networks (I guess what the US calls commuter rail), with all-day service like several Toronto routes. Several of those will interchange at the far ends with each other, and Amtrak can also use those same tracks to provide better intercity transport between the cities.
TLDR version; properly maintain what was there instead of cutting it back massively and then trying to rebuild it. Most of the south half of the London commuter belt operates trains with a 80-90mph limit - you don't need fast trains, you need regular, reliable and easy to use trains. Those are easily fixable if freight and passenger can actually work together.