Roundhouse was the trading name used by Model Die Casting Inc. of Carson City to promote and distribute their model railway systems. Active in model making since 1938 MDC produced over 1000 different models in HO, N and G scales mostly in easy to assemble kit form.

In 2004 MDC were acquired by Horizon Hobbies who at the same time purchased the Athearn model company. The Roundhouse name is today used on selective models produced under the Athearn banner.