ten years after the original society had been formed. Development The project grew fairly rapidly, with trolleybuses and some diesel buses arriving from many locations. A second building housing 14 vehicles was erected in 1972, another for 22 more vehicles in 1973, and covered space for ten vehicles has been added subsequently. Other buildings were added, including a workshop, a toilet block, a souvenir shop, stores and a theatre. Upgrading of the toilets and the construction of a new exhibition hall were funded by grants in 1995–1996, and the new hall, known as the Axholme Stores now houses a cafe. In order to allow the exhibits to operate, overhead wiring began to be erected in 1971, and the first trolleybus ran under the wires on 3 September 1972. Power was supplied by a diesel generator on the back of a Scammell lorry. This was replaced by a diesel bus engine driving a trolleybus motor acting as a generator, again all mounted on the back of a lorry, until in the 1990s power was obtained from a mains electricity supply. The vehicles in the collection have not remained static, with some moving on to other collections, some moving away to be restored elsewhere, some returning after a period away, and a few of the privately owned ones being scrapped. The organisation of the museum has developed too. The Doncaster Omnibus and Light Railway Society are still active participants, as are the renamed British Trolleybus Society, but the West Riding Transport Society was wound up, and its assets transferred to the British Trolleybus Society. The Notts & Derby Transport Society also ceased to be in the mid 1970s, but the end of trolleybus operation in Bradford resulted in the formation of the Bradford Trolleybus Association, and they have since become an active participant. The Sandtoft Transport Centre Association became the Sandtoft Transport Centre Limited in 1982, a charitable company registered with the Charities Commission. Most of the development of the site has been privately funded, and the standard of the work and organisation was recognised in 2003, when the museum achieved Registered Museum status. Further progress was made in 2010, when it was awarded Accreditation status by the Museums, Libraries and Archives Council, now part of Arts Council England. The Collection The museum houses a wide range of trolleybuses. Of the 59 listed on their website in 2019, 28 were owned by