Tank wagon, North Eastern Railway, Shell-Mex and BP Ltd saddle-mounted oil tank wagon, No 512, tank capacity 2047 gallons, built by Darlington Wagon & Engineering Company for the North Central Wagon Company and registered with the North Eastern Railway in 1889.

This tank is mounted on wooden saddles and has a wooden underframe. It features end brackets and straps which were used to fasten the tank to the undercarriage. The discharge valve is located below the tank and regulations put in place by the Railway Clearing House in 1906 meant that tanks so-fitted were not permitted to carry flammable liquids because of potential leakage. However, they were still permitted to carry less dangerous 'heavy oils' such as fuel or lubricating oil.

The wagon was restored by its last owners Shell-Mex in the 1960s, at which point some original features were substituted for modern replacements.