Question: What did the Spokane and Inland Empire Railroad merge into that operated between 1970 and 1996?
Sentence (from "Washington State Route 27"): Both highways were combined to form SR 27 during the 1964 highway renumbering and the designation was extended south to the US 195 bypass of Pullman in 1975 and north to SR 290 in 1991.
Relevant evidence: No