During the 1980s, BR began to haul timber in much greater quantities. To meet this requirement, various wagon types were converted and the OTA class was created. The OTAs served British Rail until privatisation of the network in 1996, after which many passed into private ownership where they remain today.

The BR Railfreight OTA Wagon Pack recreates typical OTA wagons as used by British Rail. It includes both clean and weathered variants, with the option to run empty or log-loaded wagons (set via the scenario editor).