NP's line to Canada ran up the east side of Lake Washington from Black River, through Woodinville, Snohomish, Arlington, Sedro Woolley, Wickersham and on to Sumas. The line carried a daily through freight from Auburn to Sumas daily (except perhaps Sunday). In steam days, helpers worked out of Woodinville and also Snohomish-Hobart, as I recall. Don't know when the last regular passenger service ran, but Casey Jones Excursions ran to Sumas in the early 1960's from Seattle's Occidental St. Yard.