What confusion, if you're geographically challenged -- EAST side of the Willamette River, railroad WEST end of Albina Yard, but geographically SOUTH end of the yard (which makes the geographic NORTH end the railroad EAST end).

I believe the interlocking takes its name from the original city of East Portland, which existed on the east bank of the river along with the separate city of Albina, where the UP built its yard. They were merged into Portland back in the late 19th Century.

The line up Sullivan's Gulch, the old Graham Line (named after a station about halfway up the grade), actually once shared the gulch with a golf course, now long gone. Where golfers once roamed is now Interstate 84.