These characterful wagons were built in three batches by the British Steel subsidiary Redpath Dorman Long from 1972 for transporting iron ore to Consett, Llanwern, and Ravenscraig. They soon became a favourite of the enthusiast as they became synonymous with the heaviest trains on the British Rail network. 

In 1980 a batch of PTAs became temporarily redundant before being snapped up by Procor. These soon found work on Mendip stone trains, going both to Foster Yeoman and ARC. Their use was in block formations from quarries at Merehead, Whatley and Tytherington to depots in London and the home counties.