British Rail Class 69

During 2000, the rail freight haulage company GB Railfreight (GBRf) obtained its first Class 66 diesel locomotive; determining the type's performance to be ideal to its purposes, procured it in large numbers; by 2021, GBRf's fleet of roughly 130 locomotives was dominated by 99 Class 66s.[5] According to Bob Tiller, GBRf's Engineering Strategy Director, while the Class 66 was affordable and considerably more reliable than its British-built counterparts, the locomotive was effectively unobtainable by the late 2010s due to its non-compliance with the latest National Technical Specification Notices. Thus, while the company sought to continue its growth, its preferred option had become unavailable other than by acquiring second-hand examples.[5]

During the 2010s, it was observed that there were no in-production diesel locomotives available at the time that could deliver the desired performance while also fitting within the UK's restrictive loading gauge.[5] Furthermore, designing one would necessitate the placing of a large and costly order that came with some risk, as a suitably compliant engine might not even fit the UK gauge at all, while an active decarbonisation strategy that sought to eliminate all diesel trains from the railway by 2040 would thus limit its lifespan considerably. Instead, GBRf examined the prospects for the conversion of existing rolling stock, akin to the reengining of the Class 47 into the Class 57.[5] Class 56, Class 58, and Class 60 freight locomotives were all studied; the Class 58 was quickly dismissed due to few examples remaining, while the Class 60s were mostly owned by other companies. The more numerous Class 56 thus became the preferred option.[5]

The company sought out available Class 56s in the hands of other companies.[5] Priority was given to those locomotives that were in good enough condition to still be moved by rail, necessitating the bogies, suspension, wheelsets, and brake equipment being functional. However, little value was placed on items such as its diesel engine or most of the control systems, which were to be replaced with systems similar, or identical, to those installed on the Class 66.[5] During June 2018, GBRf purchased 16 Class 56 locomotives from UK Rail Leasing, many of which had been out of use for a number of years.[6][7] Additionally, 56106 was acquired in an incomplete state as a source of spares and 56128 from metal recycler CF Booth.[8]

In April 2019, GBRf announced that the locomotives would be rebuilt as Class 69s by Progress Rail at its Longport facility.[5] The rebuild scheme involves the replacement of the original Ruston-Paxman RK3 engine with the EMD 710 powerplant, while newer electronic control systems based on those present on the Class 66 were also installed.[9] Initial work involved the stripping of all removable parts from each locomotive and the overhauling of all those to be retained to an as-new condition. Body repairs, usually to address corrosion, was then performed along with the replacement of all pipework.[5] The body was then subject to various alterations to accommodate the revised air intakes, exhaust (of both the engine itself and the cooler group) and the modified external lighting clusters that conform to contemporary standards. The installation of the new equipment then proceeded.[5]

GBRF stated that the complete rebuild and re-engine of each locomotive is considerably cheaper than purchasing and importing new locomotives from abroad.[10] During February 2021, 69001 underwent trials on the Severn Valley Railway prior to its arrival at Eastleigh for painting four months later.[11] On 26 May 2021, authorisation was received from the Office of Rail and Road, enabling the first locomotive to go into service two months later.[5] The initial contract was for ten units, with an option for six more.[2][12] By January 2023, seven locomotives had reportedly been rebuilt.[13]

The full fleet of seven locomotives was temporarily withdrawn from service in late January 2023 in order to "investigate faults being reported by drivers". GBRf stated that they had "become aware of issues" with the locomotives, and that the period of withdrawal – expected to last for eight weeks – would be used to implement improvements.[14]