McCormack is a retired Union Pacific locomotive engineer who is now the president of the Oregon Rail Heritage Foundation, an organization that is leading the project to build and expand the Oregon Rail Heritage Center (ORHC), a new, permanent home for the steam locomotives owned by the City of Portland. The ORHC opened its first phase in September 2012, and the main building was named in McCormack's honor: the Doyle L. McCormack Enginehouse.
McCormack is known for his work on the restoration and operation of Southern Pacific 4449, Delaware & Hudson ALCO PA 18 (preserved as Nickel Plate Road 190), as well as other noted vintage steam and diesel-electric locomotives.
He first came to Portland in 1974, from Ohio, to help restore SP 4449 to operating condition for use as the American Freedom Train during the U.S. Bicentennial celebrations in 1975–76, and he resettled in Portland in 1978.
Although mainly involved with full-size locomotives, in 1982 McCormack helped restore the Washington Park & Zoo Railway's 5/8-scale steam locomotive, No. 1, the Oregon, to operating condition by fabricating a new solid-steel frame to replace the 1959 locomotive's original frame, which had repeatedly broken.
He is probably best recognized from his cameo appearance in the 1986 film, Tough Guys, as the engineer of the steam locomotive hijacked by Archie Long (played by Kirk Douglas) and Harry Doyle (Burt Lancaster).
- Ruud, Candice (November 26, 2010). "Oregon Rail Heritage Foundation steams up to raise funds for Portland's historic locomotives". The Oregonian. Retrieved October 20, 2011.
- Larabee, Mark (November 1, 2009). "Portland's locomotives will get new $3.5 million home". The Sunday Oregonian. Retrieved 2010-07-07.
- Redden, Jim (December 28, 2007). "Running out of steam? Three locomotives chug toward homelessness, unless new site is OK'd". Portland Tribune. Retrieved July 6, 2013.
- Tims, Dana (September 20, 2012 (print edition September 21)). "Oregon Rail Heritage Center ready for grand opening Saturday, Sunday". The Oregonian. p. B1. Retrieved September 29, 2012. Check date values in:
- "The History of the Oregon". Oregon Zoo. 2005. Archived from the original on July 23, 2011. Retrieved April 11, 2012.