One of the earlier departures in the great Blackpool tram sell-off with the then impending upgrade of the tramway in mind was Blackpool Brush 636. But unlike many of the other trams which went on to pastures new and a life in preservation the tram was acquired by Stored Energy Technology of Derby who had the aim of using the tram to test an experimental motor and bogie.
Since it moved to Derby at the end of the 2004 season, 636 has been seen in many different locations including back in Blackpool for testing in 2009, a trip to Long Marston and frequency visits to the Ecclesbourne Valley Railway adjacent to Duffield mainline railway station a few miles north of Derby. In recent years it has spent most of its time at the Ecclesbourne Valley Railway where its tests are now thought to have ended with rumours earlier this year that the tram was now surplus to requirements and was being made available for purchase. No further information on that has since been released though.