In 1984, the South Yorkshire Passenger Transport Executive (SYPTE) sponsored the building of an experimental trolleybus, in connection with plans to reintroduce trolleybuses on four bus routes in Doncaster and two in Rotherham. This vehicle had a chassis built by Hestair Dennis, adapted from the standard Dennis Dominator chassis. The body was based on the Alexander 80 seat body, adapted with trolleybooms. Unusually for a British trolleybus, it included an auxiliary Diesel engine (a 48 hp 3DA Dorman) for moving away from traction wires. It had a GEC Traction motor and was capable of running at 40 miles per hour (64 km/h).
Power was supplied to the overhead (erected by Balfour Beatty) at 600 V DC from a substation at the nearby SYPTE Leicester Avenue depot.
Testing began in August 1985, on a mile-long test route alongside Doncaster Racecourse. This went from a turning circle at the end of the (private) Sandall Beat Road, alongside the racecourse, and then across Leger Way into the SYPTE bus depot. On at least one occasion it operated a revenue-earning passenger service. It is known that it was used in public service during an Open Day at Leicester Avenue Depot. The vehicle is reported to have proved satisfactory in operation.
The project was shelved in 1986 due to bus deregulation as this would mean any trolleybuses would have no protection from competing operators, and the wiring was removed in September 1993.
After the experiment finished, the vehicle was preserved, and is at the Trolleybus Museum at Sandtoft where it is now actively receiving electrical repairs.
The vehicle can be viewed at the Museum.