Steam locomotive, replica, Great Western Railway, (2-2)-2-2 broad gauge locomotive "Iron Duke", and tender.

The Great Western Railway Iron Duke class was a class of broad gauge steam locomotives design for express passenger work.

The GWR was designed by Isambard Kingdom Brunel with a gauge of 7ft ¼ inches, whereas standard gauge was 4ft 8 ½ inches. Initially the government accepted that lines would be built with broad gauges, but it was eventually decided that all railways in the UK should have the same standard gauge. The GWR was converted from broad to standard gauge with the last section being converted in 1892.

Locomotives of the Iron Duke class were extremely fast, able to reach speeds of approximately 80mph. The original Iron Duke locomotive was built in 1847 and was one of the first batch to be built, and named in reference to the Duke of Wellington. It was withdrawn in 1873.

In 1985 a full-size working replica of Iron Duke, capable of being steamed, was commissioned by the the Science Museum. While not a perfect facsimile of the first engine of the class, the Iron Duke replica represents the class as a whole and some of the changes made over its working life.

The firebox, boiler, cranks, and cylinders were taken from a Hunslet Austerity locomotive and the smokebox was specially constructed. The replica was built by Resco (Railways) Ltd.