In 1944 a new specification was agreed between the private owners, the Petroleum Board and the railways companies featuring a welded tank barrel and new mounting method. Welded construction produced a much stronger barrel by eliminating all the joints and fasteners of the earlier riveted construction methods. Welded tank barrels needed much less support, so the timber saddles or cradles and end stanchions could be dispensed with, replaced by a central steel 'anchor' of riveted or welded construction fixing the tank to the underframe.
The majority of these wagons were built from 1949 and into the early 1950s with Class B tanks being the predominant type. The last could be found in service until the early 1970 with a few examples making it into preservation.
Changes were made to the drawgear at the same time. As the underframe was to be of steel construction the new RCH specifications allowed the 'continuous drawgear' with its central cradle to be replaced with 'short' drawgear where short, separately sprung coupling hook drawbars were attached to structural frame members behind the headstock, transferring pulling forces to the wagons central sill beams. These features being quite obvious below the ends of the tank barrels.
Features of the Dapol Anchor Mounted Petroleum Tank Wagon Include
- Extremely detailed and accurate body shell and chassis
- Many separately added fine details, including, where applicable, long and short fillers, correct filler position, with and without ladders and platforms and where relevant heating pipes.
- Sprung metal buffers
- Metal sprung coupling hook and three link coupling
- Finely profiled wheels with sprung axles for smooth running even on uneven track
- Superbly applied livery