The fictional story.
The Huff and Puff Railroad, created by a merger of the Elk River Railroad and the Thatcher's Inlet Railroad, was considering rebuilding their old trestle over Grand River when the CP Railroad offered them the use of the right of way of their trackage from the sawmill, over their Grand River Bridge and on to Thatcher's Inlet. The Huff and Puff would allow them to build a gravel dock in the harbour. The deal was struck, to the benifit of both railroads.
Now for the real story. Parts of the branchline were inspired by the Elk River Railroad and the Thatcher's Inlet harbour, by Bob Hayden and Dave Frary, that were featured in Railroad Model Craftsman.
I had been struggling with how to interchange rolling stock between the mainline and the branchline and how this would work with our Train Order cards. Sure we could have a interchange siding, but what if the branchline isn't operated in a session, the cars would pile up, and how would the train order to pick up and deliver rolling stock, which may or may not have been delivered, look? Then the idea that the branchline was too long, and occupied too much area, and should be terminated at the corner of the peninsula, surfaced. Too bad I thought, I like the branchline. Then the non-seaport, gave the mainline a harbour. Great lets make the little harbour part of the branchline.
Now both lines exchange rolling stock in the harbour, except the mainline gravel dock, and the branchline has its own train orders using rolling stock at the harbour and the 2 branchline towns. Each line operates with or without the other. An added bonus is the branchline gets a longer run for both the passenger and freight service. Note the Grand River Bridge may or may not be built in the narrow area near the end of the peninsula.