Question: Into what company did the railroad which had operated the Twin Cities Zephyr merge in 1970?
Sentence (from "Chicago, Burlington and Quincy Railroad"): Commonly referred to as the Burlington or as the Q, the Burlington Route served a large area, including extensive trackage in the states of Colorado, Illinois, Iowa, Kansas, Kentucky, Missouri, Montana, Nebraska, Wisconsin, Wyoming, and also in New Mexico and Texas through subsidiaries Colorado and Southern Railway, Fort Worth and Denver Railway, and Burlington-Rock Island Railroad.
Relevant evidence: No