In 1944 a new specification was agreed between the private owners the Petroleum Board and British Railways, the major difference from the 1927 design being that the saddle and cradle timbers, and the end stanchions were abandoned, and the tank anchored to the underframe by a central steel anchor of riveted or welded construction the so called anchor mounting. The supporting saddles were also fabricated from steel.
 The majority were built 1949 and into the early 1950s with Class B tanks being the predominant type to be built. They remained in service up to the early 1970s. A few examples making it into preservation along with  several of the larger 20 ton version.
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
 
