passenger service. Because of a design requirement that the class be able to function as normal locomotives if so required, a full driver's cab is also provided at the Number 2 endbut the locomotive's maximum speed is reduced to when this cab is at the front of a train. During the privatisation of British Rail ownership of the Class 91 fleet passed to Eversholt Rail Group, which in turn leased the fleet to its various operators. Eversholt put all 31 locomotives through a £30million heavy overhaul and refit process () between 2000 and 2003, seeking to improve the fleet's reliability. Rail Magazine described it in March 2001 as being necessary because "eight out of ten failures on Class 91s were caused by the sub-standard electrics", and further noted that problems with relays in particular were the "third-biggest" cause of failures. The refit was performed by Adtranz (later Bombardier Transportation), with technical support from Alstom, and involved upgrades to the bogies, electrical systems, air compressors, and parking brakes; alterations to the cab layout at the Number 1 end; the replacement of the original gearboxes with newly designed Voith models; and the installation of TPWS and a new air-cooling system. Overhauled units had their numbers increased by 100; thus 91001 became 91101 and so onwith the exception of 91023, which was renumbered 91132 due to sensitivity around its involvement in both the Hatfield and Selby accidents. During the overhaul process, GNER hired in Class 90 locomotives to provide cover for their services. In November 2012, number 91114 had a second pantograph added as a pilot project conducted jointly by Eversholt, East Coast, DB ESG, Wabtec, and Brecknell Willis. The new design uses the same mounting positions as a conventional pantograph but pairs two pantograph arms in an opposing configuration. If there is an ADD (Automatic Dropping Device) activation or the pantograph becomes detached, the train can keep going, so the system provides redundancy in the event of a pantograph/OLE failure. Speed records Locomotive 91010 (now 91110) holds the British speed record for electric locomotives, reaching while on a test run down the East Coast Main Line's Stoke Bank on 17 September 1989. Locomotive 91012 (now 91112) holds the separate record for the fastest non-stop journey between London King's Cross and ; 3hours29minutes on 26 September 1991, running within the speed limit but hauling a shortened set of only five coaches plus DVT.