![Image](http://pic100.picturetrail.com/VOL761/13303934/24761111/413430734.jpg)
Following publication of the British Railways Modernisation Plan in 1955, it became clear that future passenger and freight schedules would be revised for faster workings, utilising high-speed Diesel, Electro-Diesel and all Electric Locomotives. Railway rolling stock would, therefore, be redesigned and constructed to operate within conditions envisaged under the new modernisation programme. Whilst future Railway planning covered the design and construction of all stock, including passenger and freight, no general provision had been made for railway tank wagons carrying petroleum products which normally did not operate at speeds in excess of 45mph and were subject to frequent examinations during transit.
In 1956 Esso Petroleum Co. Ltd. approached British Railways to design a new tank wagon capable of maximum capacity on four wheels within the 35-ton gross weight permitted under high-speed conditions. Three prototype wagons were designed and constructed and, following certain trials and shunting tests, the Mark I was approved by British Railways. Subsequently over 800 of this type of wagon were ordered by the Esso Company from various builders. Two classes of vehicle were built, Class A for carrying Petrol and Highly Inflammable products, and Class B for carrying Fuel Oils, Diesel Oils and Kerosenes.
The Class B tank barrel is fitted with steam coils to assist the offloading of heavy fuel oils. Discharge of load is controlled by internal rod and plug, operated by the hand wheel located on top of the tank.
The R1 Type 3 boxing with scratched parts
![Image](http://pic100.picturetrail.com/VOL761/13303934/24761111/413430735.jpg)
The 02656-3 Type 4 with metal wheels
![Image](http://pic100.picturetrail.com/VOL761/13303934/24761111/413430736.jpg)
The Dapol C36 with many scratched parts
![Image](http://pic100.picturetrail.com/VOL761/13303934/24761111/413430737.jpg)