7029 was constructed by BR at Swindon in May 1950 as one of the last batch of 'Castles'. In its present condition it represents the final development of the class incorporating the modifications made in the 1950s. Outwardly, the only indication of enhanced performance is the double chimney, but internally the boiler has a four-row superheater and altered smokebox draughting arrangements. 7029 was the last 'Castle' to remain in BR service and was withdrawn in 1965.

But prior to withdrawal, 'Clun' achieved its finest moment at the head of an enthusiasts special commemorating the end of express steam working on the Western Region in 1964. On the descent of Wellington bank in Somerset, the locomotive achieved a top speed of 96 mph on the fastest ever recorded timing over the arduous route from Plymouth to Bristol. She hauled the last steam service train from Paddington in 1965 and was also the last steam engine to leave the former Snow Hill station with a passenger train.

Since preservation, the engine has travelled widely on excursions and to Open Days in London, Newcastle, Carlisle, Leeds, York, Liverpool, Stratford. Didcot and Hereford. During 1985, 'Clun Castle' played a prominent part in the Great Western Railway 150th Anniversary celebrations by hauling main line trains as far away as South Wales and Cornwall.

Clun Castle was the last steam engine to haul a train from the original Moor Street station before it closed making way for the 'new' Moor Street station situated on the through lines to Snow Hill.  Indeed this was the last train out of the original Moor Street station before it was closed.

Clun Castle the first steam locomotive to use the new Snow Hill station which was opened by His Royal Highness the Prince of Wales who rode on the footplate through the Snow Hill tunnel to Moor Street and on to Tyseley.  Clun has seen spells of duty at the Great Central Railway & Gloucestershire & Warwickshire Railway, and was a popular engine on the Steam Locomotive Driving Experience Courses which were run at Tyseley. Her current 'certificate' ran out at the end of 2001 and she now awaits her turn for overhaul in Tyseley Locomotive Works.

An appeal to fund the overhaul and return of Clun to the mainline is to be formally launched at the Tyseley 100 Open Weekend on 28/29 June 2008.