Not to pick nits, but GN never operated on the section parallel to I5 which was known as the Lakeview sub in later years. The Prairie line ( which GN and UP used until the Pt Defiance line) contunued from Lakewood south through Ft Lewis to Yelm and Tenino where the alignment remains the same. THe Lakeview sub was built to reach Olympia and Lace and then on to Gate for the remainder of the run to Grays Harbor. When the Nisqually line was built they roughly followed the alignment of what became the Lakeview line from St Clair to Nisqually.

And no, I have no idea why the BN called it Lakeview, since the town is Lakewood.

Another interesting note, UP has access to Ft Lewis for military movements. Another interesting note, the prairie line was intact until the single tracking of Nelson Bennett tunnel in the 80's for over dimensional shipments. What became BN train 111 ( Seattle to Pasco priority) handled overheight Boeing cars on the Prairie line