David J. Hayes explains "The four covered hopper wagons at the rear of this short Speedlink feeder consist are what appear to be brand-new PAA types (built by Standard Wagon in 1981) used for transporting china clay from clay dries such as Goonbarrow, Cornwall, to the Tullis Russell paper mill at Auchmuty, Fife, which was reached via a branch from Markinch. Such traffic around this time would have been routed via Severn Tunnel Junction Yard from where it would then be trunk Speedlink-hauled to Scotland, usually by way of the North & West "Welsh Marches" line axis to Shrewsbury and Crewe, and then the WCML to Mossend Yard. The two two-axle vans may have been in use for bagged clay or perhaps for Government Stores (MoD) business. "