Chassis: Sunbeam S7A (3 axle)
Chassis No. TFD 74375
Motor : Metropolitan Vickers Type 210 CVI (150 hp)
Bodywork: East Lancs H40/32R
Length 30ft 0in, Width 7ft 6in.
Unladen Weight : 9tons 2cwts 0qtrs
Entered Service : 3 December 1959
Withdrawn : 11 July 1968
631 was the first of a batch of 10 Sunbeam S7A trolleybuses which entered service in Huddersfield in November/December 1959 to replace some of the ageing rebuilt Karrier E6 trolleybuses. These were Huddersfield’s last new trolleybuses and also the last three-axle trolleybuses built for service in the United Kingdom. They followed the style of the previous Huddersfield trolleybuses (3-axle, double-deck, 7' 6" wide) to fit in with the rest of the fleet, despite the regulations having been relaxed a few years earlier which would have enabled these trolleybuses to have been built as two-axle. They were not particularly well-liked by the Huddersfield crews, who tried to have alternative vehicles allocated to them.
631 led an uneventful life during its 9 years in service. However, when the trolleybus system in Huddersfield was abandoned in July 1968 the Huddersfield Trolleybus Preservation Society (HTPS) secured 631 for preservation. She was used for two very successful enthusiast tours of other systems before she was 'retired' to museum work. On 27 October 1968 631 toured the Reading system with Belfast 168 and she ran another tour in Bournemouth on 24 November 1968.
631 was transferred to the site which became the Sandtoft Transport Centre in 1969. Following the demise of West Yorkshire Transport Circle (one of the groups which grew out of the HTPS) 631 was transferred to BTS ownership. Arguably 631 has been Sandtoft's most reliable service trolleybus over the years and is still in good condition.
In 2012 it was decorated in true Huddersfield style to mark the Queens Diamond Jubilee. on 10 January 2013 631 was towed to Swindon where it will be externally repainted back into Huddersfield livery and also a partial internal repaint.will be carried out. It is hoped that the seats can be re-upholstered if funds allow. Once completed it is hoped to re-commsion 631 back into service over the 2013 August Bank Holiday.