In the early 1990s, National Power was developing plans to run its own coal trains to Drax Power Station. Trials had taken place during the autumn of 1992 using Tiphook KPA bogie hopper wagons. To realise its plans, National Power ordered five locomotives along with a batch of 85 hopper wagons. The first wagons were delivered in May 1995 and they soon received the TOPS code JMA. In 1998 National Power sold its rail operations to national freight operator EWS. Whilst much of the fleet was stored out of service, in early-2009, those JMAs that were still in service were fitted with new bogies, receiving the TOPS code HKA. As is often the case with freight stock, the wagons were not repainted and many still carried National Power branding.