Diesel-electric No.21 was proposed as a replacement for No.17 Viking and after initial requests for government funding for a new build were rejected on cost grounds, the resultant hybrid was decided upon, from the North Carolina manufacturers Motive Power Solutions Inc. The unit is the first locomotive to join the fleet since No.18 Ailsa and arrived on the railway in December 2013 where is made an appearance during the Santa Train weekends. The underframe, bodywork, engine, generator and controls were provided new while the bogies were modified from a former General Electric industrial locomotive. It is the first locomotive on the railway to feature a cab at both ends, the initial plan for a steeple cab being rejected The first tests exposed overheating issues and after these were rectified the unit carried out several passenger duties but was still beset with teething issues. It entered semi-regular service in August 2019 being based out of Port Erin while No.8 Fenella was receiving attention in the workshops, but this work was short lived as further mechanical issues were discovered, this being the most recent revenue-earning service for the locomotive. Technical issues currently being investigated are centered around slipped tyres, software problems, oil leaks, transmission issues, all of which are in the process of being rectified.