Line through downtown Niagara Falls

a lot of Chessie System & Penn Central traffic also on that line through the Clifton Hill (tourist trap) part of Niagara Falls Ontario at one time. Tommy-in old city of Niagara Falls Ont, (not the tourist trap), the old NYC bridge to the US is adjacent to the CN Bridge to Niagara Falls NY.
Maybe if you google map the VIA Station in Niagara Falls, it will give you the aerial view of both bridges.
We once rode the Rainbow also from St. Thomas Ontario (after taking VIA/CN to London the previous day and a Charterways bus to St. Thomas) to Fort Erie Ontario and then took the CP Rail Budd Car from Fort Erie back to Oakville (over the Penn Central-TH&B-CP Rail and CN!). Glad I got a chance to ride the Canada Southern. The Rainbow still used E units at that time and usually had an ex NH "County Series" combine in the consist. And as mentioned above, the train was sealed in Canada, except for the one car for "shorts and locals" which made the customs relatively easy. When the train was diverted to Toronto from Detroit and received the name change (Maple Leaf), VIA became responsible for the Nia Falls-Toronto crewing, etc. What is sad is how long is now wasted for Border Clearance (I believe almost two hrs is what is shown for Nia Falls Ontario to Nia Falls NY.) No preclearance is performed in Toronto like was done 40 years ago on Int'l runs!

The line in question was "officially" the Canada Southern (CASO), a "paper" railroad controlled by Michigan Central, which was itself leased by NYC. In one of the more bizarre events following the Penn Central bankruptcy, the directors of the Michigan Central attempted to pay themselves a very large dividend on their CASO stock, from per diem payments that had accumulated in a CASO account. That payment would have been sufficient to permit MC to undertake an independent reorganization. The bankruptcy judge, however, was having none of it.

Lehigh Valley's attorneys tried something similar, and also failed. The only leased property to "escape" from PC was Providence & Worcester. But I digress...

The CASO route diverged from the CN just west of the current Niagara Falls Amtrak station and used its own bridge across the Niagara River, just upstream of the "Rainbow Bridge" used by Amtrak today. The track is still in place on the bridge and on the NY approach, but there is a large chain link barricade on the bridge topped with razor wire.

From the bridge, the track ran through downtown Niagara Falls, ON and through the Fallsview neighborhood, now a cluster of large hotels and one casino. I stayed in the Hilton overlooking the Falls a few years ago, and the ROW had not yet been turned into a walking path.

Less than a mile from Fallsview, there was a wye to a connecting track over to CN, and then a junction with the line from Black Rock, NY via Fort Erie. At that point, the line became double track (and was shared with Toronto, Hamilton, & Buffalo). It went under the Welland Canal in a tunnel, and then TH&B split off to run to Hamilton. CASO was double track from that point all the way to Windsor, and also hosted N&W (former Wabash) and CSX (former C&O) trains.

Conrail routed traffic away from CASO, and in the 1980s the second main was removed. A decade later, the remaining trackage was turned over to CN (IIRC).

Too bad some one did not have the "vision" to turn that line into a Light Rail system which I suspect could have been an tourist attraction as it crossed the bridge.