Railroad Name
Columbia & Puget Sound Railway
Duluth Missabee & Iron Range
English Lumber Company
Great Northern
Interstate Transfer Railway
King Street Terminal
Milwaukee Road
Northern Pacific
Pacific Northwest Traction Co
Pugit Sound & Cascade
Puget Sound & Pacific
Puget Sound & Willipa Harbor Railway
Oregon Washington RR & Navigation
Schafer Brothers Logging
Spokane, Portland & Seattle
Those listings in the synopsis & document column's in blue are there because a letter from C O Jenks (GN) to the NP dated April 15th 1921 sets out those locations that the GN wishes to be interlocked.

The NP response is not as far as I know available. It would help if it was.