The original streamlined shape of the Coronation class arose from tests conducted by the LMS Research Department on Sir William Stanier’s previous development of the Princess Royal class locomotives. Stanier was said to be ambivalent about the economic value of streamlining, but was aware of the publicity value that such a design would generate.

6221 Queen Elizabeth was the second of the class to be built, leaving Crewe Works in June 1937 for Camden Shed and covering just under 31,000 miles that year, compared to nearly 68000 in 1938.

In 1939, 6221 moved to Crewe North for a month, briefly returning to Camden before being allocated to Polmadieon November 25, 1939. Whilst here, the streamlined casing was removed on June 28, 1946.