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.