LMS Ivatt 10000/10001
LMS 10000 and 10001 were the first main-line diesel locomotives built in Britain, a pair of 1,600 hp diesel-electric prototypes designed by H. G. Ivatt, the last Chief Mechanical Engineer of the London, Midland and Scottish Railway, in collaboration with English Electric. 10000 was outshopped from Derby Works in December 1947, just three weeks before nationalisation, specifically so that it would carry the LMS badge and be remembered as an LMS locomotive. 10001 followed in July 1948, by which time the LMS had ceased to exist and the new locomotive emerged in British Railways livery. Under BR they were classified D16/1, paired in the classification scheme with the three diesel-electrics built shortly afterwards by O. V. S. Bulleid for the Southern Region (D16/2).
The design brief, announced in March 1947, was for two 1,600 hp diesel-electric locomotives capable of 100 mph and able to handle express services such as the Royal Scot. Ivatt and his team, working closely with English Electric and drawing on engineering relationships established with the Vulcan Foundry, produced a 1Co-Co1 layout: two three-axle powered bogies with an idler axle ahead of each, designed to keep the maximum axle load within main-line route limits while distributing the weight across eight axles in total. Each locomotive carried a single English Electric 16SVT Mk I prime mover, a 16-cylinder V four-stroke driving a DC main generator that supplied six DC traction motors, one per powered axle. The bodies took an obvious cue from the streamlined cab style of contemporary American General Motors F-units, with twin nose-end doors to permit nose-to-nose multiple working as a single 3,200 hp unit.
To working crews of 1948 the twins were locomotives of the steam age in everything but the prime mover. They were vacuum-braked, two-man-crewed, and fitted with water scoops to refill their train-heating boilers from troughs as a Stanier Pacific would. Steam heat for the train came from a Spanner oil-fired boiler. Servicing was done at Camden, Crewe, Willesden, and Polmadie alongside Stanier's express engines and Black Fives.
In service the pair found their natural form working as a unit. Singly, neither locomotive could match the front-rank express duties Ivatt had originally hoped for: 10001 recorded 82 mph on a down gradient with a 490-ton train on the "Red Rose", but 10000 was found to be marginal on the heavier expresses out of St Pancras and Euston. Worked as a pair, however, they comfortably handled the Royal Scot between Euston and Glasgow, were used to demonstrate the diesel-electric case on the Settle & Carlisle and at Shap, and were even rostered on a 1,100-ton coal train between Rugby and Willesden, climbing the 1-in-133 to Tring Summit at 25 mph. They worked as far north as Aberdeen on at least one occasion. Boiler-related train-heating problems meant they often spent the winter on freight workings and the Royal Scot in summer.
In March 1953 both engines were transferred to the Southern Region for direct comparison with Bulleid's diesel-electrics 10201, 10202, and 10203. They appeared in early-crest semi-gloss black with a silver waistband and roof, and were regular performers on Waterloo–Weymouth services including the prestigious Royal Wessex. They returned to the London Midland Region in spring 1955, were overhauled at Derby, and emerged in BR Brunswick green, 10000 receiving the new livery in September 1956. The famous raised "LMS" lettering on 10000's bodyside, which Ivatt had quietly declined to remove despite repeated instructions from BR, finally came off in March 1951 only after his retirement.
The pair's final years were a slow decline. 10000 was withdrawn in 1963 and stripped to keep 10001 running; 10001 itself lasted until 1966. Both were stored, then sold for scrap and cut up at Cox & Danks, North Acton, in 1968. Preservation attempts failed: 10000 was offered to Clapham Railway Museum but refused on space grounds and as not representing a class, and 10001 was at one point hidden at Willesden depot and "overlooked" twice before finally going to the cutter's torch. The Preservation of British Transport Relics formally declined to keep either locomotive on 26 July 1967.
The class's real legacy was technical rather than material. The English Electric 16SVT prime mover proved the diesel-electric formula for British main-line use, and its derivatives went on to power Classes 20, 31, 37, 40, and 50, almost the entire first generation of BR diesel-electric main-line traction. The bogie design, with its equalising-beam suspension, set patterns followed across British diesel design for decades. From 2011 the Ivatt Diesel Re-creation Society has been building a working replica of 10000, using a contemporary EE 16SVT Mk I engine, ex-EM2 (Class 77) bogies of the same Metropolitan Vickers design, and a Class 58 chassis as the basis for the new locomotive.
Design and development
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 1Co-Co1: two three-axle powered bogies, each with a leading idler axle ahead of the powered three. 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 1Co-Co1 layout was followed on BR's first-generation Class 40 (10001 successor in spirit) and on 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.
Service and withdrawals
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.
Identification features
Numbers and names
LMS/BR: 10000 and 10001. Both retained their original numbers under British Railways. Classified as BR D16/1 from c.1960; further amended to 16/8 in 1962. Some secondary sources cite a TOPS Class 34 number, but TOPS post-dated the scrapping of both locomotives and no official BR document records the assignment.
Notable locomotives
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.
Allocations and regions
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.
Livery history
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.