LMS 10000 / 10001

The LMS announced its intention to build main-line diesel locomotives in March 1947, the project championed by H. G. Ivatt, son of the Great Northern Henry Alfred Ivatt, and the LMS's last Chief Mechanical Engineer. The brief was a pair of 1,600 hp diesel-electric prototypes capable of 100 mph and able to handle the Royal Scot single-handed or work harder duties as a coupled pair. Speed of delivery was a priority: the LMS was four years from nationalisation and then suddenly less than a year from it, and Ivatt wanted his design to enter service in LMS ownership.

The locomotives were designed and built at Derby Works with English Electric supplying the prime mover, main generator, auxiliary generator, traction motors, and control system. The bogies were a Metropolitan Vickers design with equalising-beam suspension, a layout that proved enduring and was reused on the EM2 (later Class 77) electric locomotives of the 1950s. The Vulcan Foundry, with whom the LMS had a long working relationship, supplied components.

The chosen wheel arrangement was Co-Co: two three-axle bogies with all six axles powered. The idler axles were not for guidance, both bogies were symmetrical in operation, but to spread the considerable weight (about 128 tons per locomotive) over eight axles, keeping the maximum axle load within main-line restrictions. The English Electric 16SVT power unit was carried over to BR's first-generation Class 40 — which used a 1Co-Co1 layout, adding a carrying axle at each end — and to many subsequent main-line diesels.

The English Electric 16SVT Mk I prime mover, a 16-cylinder V four-stroke of approximately 1,600 bhp at 750 rpm, was the most consequential single component. The 16SVT and its later derivatives powered Classes 20, 31, 37, 40, and 50, making the LMS twins the ancestors of nearly the entire first generation of BR main-line diesel-electric traction. The Mk II development of the same engine is still encountered on heritage railways today.

10000 was completed at Derby in late November 1947, formally presented to the press on 5 December 1947, and made a public demonstration return run from Euston to Watford on 18 December 1947. It entered ordinary service on the Midland route from St Pancras in February 1948. 10001 was completed in July 1948 under British Railways and went to traffic on similar duties. The two prototypes remained the only locomotives of their kind, the proposed LNER diesel scheme that Ivatt's design might have served instead never materialised, and BR's subsequent diesel programme was structured around new BR-specified Pilot Scheme designs from 1955 onwards.

10000 went into ordinary service in February 1948 on the St Pancras–Manchester route, with timings set against a Class 5X 4-6-0 express schedule and a 393-ton tare twelve-coach train including a dynamometer car. The locomotive met the schedule on the day's tests. Once 10001 joined it from July 1948, the pair operated singly on a variety of routes, Euston–Blackpool, London–Crewe, London–Liverpool, and 10001 trialled on London–Glasgow workings. On the Red Rose, 10001 was recorded at 82 mph on a down gradient with a 490-ton train.

The locomotives' real strength was as a pair. From 1949 they regularly worked the Royal Scot together between Euston and Glasgow, completing return runs in a single day, a notable improvement on steam-era schedules. Freight work included Camden–Crewe expresses (meeting a 45 mph average with a 500-ton train) and a notable 1,100-ton coal working from Rugby to Willesden, climbing the 1-in-133 to Tring Summit at 25 mph. They also worked on the Settle & Carlisle, reached Perth on regular service, and made at least one trip to Aberdeen.

Train-heating boiler reliability problems sometimes left them unable to provide steam to the train, and as a result they were often rostered on freights in winter and reserved for the Royal Scot in summer when train heat was not required.

In March 1953 both locomotives were transferred to the Southern Region for direct comparison with Bulleid's diesel-electrics 10201, 10202, and 10203 (D16/2), then in service on the Waterloo–Weymouth line. They worked the Royal Wessex and other South Western expresses until spring 1955, when they returned to the LMR via a Derby overhaul that brought the new BR Brunswick green livery for 10000 in September 1956.

Through the late 1950s the pair continued working West Coast main-line duties, but with diminishing intensity as the BR Pilot Scheme diesels arrived and then the production Type 4 fleet from 1959 onwards. 10000 was withdrawn in 1963, a particular irony given its status as the first British main-line diesel, and was stripped at Derby to keep 10001 running. 10001 itself was withdrawn in 1966. Both locomotives were stored, then sold for scrap. The Preservation of British Transport Relics declined to keep either on 26 July 1967 (10000 had been offered to Clapham Railway Museum but rejected on grounds of space), and both were broken up at Cox & Danks, North Acton, in 1968.

10000, the first main-line diesel locomotive built in Britain. Presented to the press at Derby Works on 5 December 1947 and demonstrated at Euston station on 18 December 1947 with a return run to Watford. Outshopped only three weeks before nationalisation specifically so that it would carry the LMS badge. Carried raised 'LMS' bodyside lettering until March 1951, Ivatt famously and quietly declined to action BR's instructions to remove the lettering, which was finally taken off only after his retirement. Withdrawn in 1963 and stripped to keep 10001 in service. Scrapped at Cox & Danks, North Acton, in 1968.

10001, sister locomotive completed in July 1948 under British Railways. Carried BR livery from new and never wore LMS markings. Hidden at the back of Willesden depot at one stage during withdrawal, having been 'overlooked' for removal at least twice by railwaymen who hoped for its preservation. Withdrawn in 1966 and scrapped at Cox & Danks, North Acton, by December 1968.

New-build 10000 (under construction), the Ivatt Diesel Re-creation Society, formed in 2011, is building a working replica of 10000 from contemporary and re-purposed components. The project has secured an original Mk I English Electric 16SVT prime mover (from a 1947 batch with around 500 hours' running, originally built for an unfulfilled Egyptian Railways order), two ex-EM2 (Class 77) Metropolitan Vickers bogies, and a stripped Class 58 chassis as the structural base. Intended for use on heritage railways rather than the main line.

Pre-grouping inheritance (none): a wholly post-war design with no antecedent fleet.

LMS / British Railways London Midland Region (1947–1953): based primarily at Camden and Willesden in London for West Coast main-line work, with Polmadie (Glasgow) for the Glasgow end of the Royal Scot. Servicing was carried out alongside Stanier Pacifics and Black Fives at the same depots, there was no diesel-specific servicing infrastructure to begin with.

British Railways Southern Region (March 1953, Spring 1955): transferred for direct comparison with Bulleid's 10201, 10202, and 10203 (D16/2). Used regularly on the Waterloo–Weymouth line, including the prestige Royal Wessex express introduced for the 1951 Festival of Britain. Carried early-crest semi-gloss black with silver waistband during this period.

British Railways London Midland Region (1955–1966): returned to the LMR after a Derby overhaul, in BR Brunswick green from 1956. Continued on West Coast main-line work, including the Royal Scot as a pair, but with declining intensity as Pilot Scheme diesels and then the BR Type 4 fleet arrived from 1958 onwards.

10000, LMS black/silver (December 1947, March 1951): very dark grey-black with silver lining and waistband, polished raised 'LMS' bodyside letters. Ivatt did not pass on BR's instructions to remove the LMS lettering; it stayed in place until after his retirement.

BR semi-gloss black (early 1950s): both locomotives carried plain black with the early lion-and-wheel emblem and a silver waistband and roof during their Southern Region service from 1953 to 1955.

BR Brunswick green (1956–withdrawal): applied at Derby after the return from the Southern Region. 10000 received the new livery in September 1956. Both carried Brunswick green for the remainder of their working lives, with the early lion-and-wheel emblem replaced by the later BR crest from c.1957–58.

10001, BR livery from new (July 1948): emerged from Derby in plain black with the BR symbol later applied. Never carried LMS markings.

Neither locomotive survives. Both were scrapped at Cox & Danks, North Acton, in 1968 after the Preservation of British Transport Relics declined to retain either on 26 July 1967. 10000 had been offered to Clapham Railway Museum but rejected on the grounds that it did not fit the available space and 'did not represent a class', a verdict that overlooked its position as the first British main-line diesel. 10001 spent some time hidden at the back of Willesden depot, having been 'overlooked' for removal at least twice by railwaymen sympathetic to its preservation, but was ultimately broken up alongside 10000.

The Ivatt Diesel Re-creation Society, formed in 2011, is constructing a working new-build replica of 10000. Key components secured to date include an original Mk I English Electric 16SVT prime mover (from a 1947 production batch, with approximately 500 hours' running time, originally built for an unfulfilled Egyptian Railways order); two ex-EM2 (Class 77) Metropolitan Vickers bogies of the same fundamental design as the originals (with springs to be uprated for the new locomotive's weight); and a Class 58 chassis as the structural starting point. Other components are being sourced from preserved BR diesel classes (notably 56 and 58) and fabricated new where necessary. The completed locomotive is intended for heritage railway use rather than main-line operation.