Krauss-Maffei close-up By | January 6, 2023 Email Newsletter Get the newest photos, videos, stories, and more from Trains.com brands. Sign-up for email today! Get Updates Rio Grande 4001, a diesel-hydraulic built by Germany’s Krauss-Maffei, fills the window of a caboose cupola on Oct. 11, 1963. The exotic unit was testing in helper service between Denver and the Moffat Tunnel. R. P. Parsons photo