The British Rail Class 56 is a type of diesel locomotive designed for heavy freight work. It is a Type 5 locomotive, with a Ruston-Paxman power unit developing 3,250 bhp (2,423 kW), and has a Co-Co wheel arrangement. Enthusiasts nicknamed them "Gridirons" (or "Grids" for short), due to the grid-like horn cover on the locomotive's cab ends fitted to nos. 56056 onwards. Under its Romanian railway factory nomenclature, the locomotive was named Electroputere LDE 3500, with LDE coming from Locomotivă Diesel-Electrică (Diesel-Electric Locomotive) and the 3500 being the planned horsepower output.
The Class 56 fleet was introduced between 1976 and 1984, a total of 135 examples were manufactured. The first 30 locomotives (56001 - 56030, factory classification LDE3500) were built by Electroputere in Romania, but these typically suffered from poor construction standards and many were withdrawn from service early for extensive rebuilding before re-entering revenue service. The remaining 105 locomotives were built by British Rail Engineering Limited (BREL) at Doncaster Works (56031 to 56115) and Crewe Works (56116 to 56135).
Background
Origins
During the early 1970s, it became clear to British Rail planners that a new Type 5 locomotive to handle heavy freight services would be ideal. However, ambitions to produce such a fleet were somewhat hamstrung by cutbacks at many of Britain's major railway workshops, having lost many skilled staff through multiple restructurings and cost saving drives; according to railway author Rodger Bradley, such moves proved to have come at a substantial long term cost to the nation's railway engineering capabilities.
Accordingly, in 1974, BR placed an order for 60 freight locomotives, which were originally intended to be separately constructed in two batches of 30 at BREL's Doncaster Works and Brush Traction, Loughborough respectively. However, Brush had already reached the maximum capacity of their Loughborough site via several unrelated projects, making it unrealistic to perform the work in-house as had been foreseen. To overcome its constraints, the company's managers opted to subcontract its batch to the Romanian locomotive manufacturer Electroputere.
On 29 April 1977, the first Class 56 locomotive to be constructed by Electroputere was handed over to British Rail, having been transported from Romania by ship via the port of Harwich. At one point, it was reportedly planned to deliver 20 locomotives each year; however, this ambitious schedule did not come to pass without consequence. The 30 Romanian locomotives (Nos. 56 001 – 56 030) were found to have a relatively poor build quality; to effectively address this, the majority had to be withdrawn from service for extensive rebuilding within their first few years of operation, after which they were re-introduced to service with better performance.
Follow-on orders and work redistribution
At an early stage of the programme, BR had indicated its intention to place a follow-on order for the type following the delivery of the first 30 locomotives. Accordingly, the number ordered was increased to 135 and they were numbered as follows: 56001 to 56030, built by Electroputere, Romania 56031 to 56115, built by BREL, Doncaster Works 56116 to 56135, built by BREL, Crewe Works
BREL's Doncaster Works were in heavy demand at this time and its resources would be stretched to meet these targets due to a lack of skilled personnel to manufacture mechanical components. Instead the Ashford, Eastleigh and Swindon Works produced sub-assemblies; roofs, fuel tanks and cab frames were produced at Ashford, while cab desks were built at Eastleigh, and radiator housings were supplied from Swindon. Final assembly was transferred from Doncaster Works to Crewe Works, allowing Doncaster to commence work on the new Class 58 heavy freight locomotive.
As a consequence of poor experiences with the early Romanian-built members of the class, the subsequent locomotives featured significant modifications. It had been largely due to the initially negative experiences with the Class 56, which had caused dissatisfaction amongst several of British Rail's freight customers, that BR officials had initiated work on the Class 58 and then the Class 60.