The LSWR N15 class was a British 2–cylinder 4-6-0 express passenger steam locomotive designed by Robert W. Urie. The class has a complex build history spanning three sub-classes and eight years of construction from 1918 to 1927.
Following the grouping of railway companies in 1923, the LSWR became part of the Southern Railway (SR) and its publicity department gave the N15 locomotives names associated with Arthurian legend; the class hence becoming known as King Arthurs.[4] The Chief Mechanical Engineer (CME) of the newly formed company, Richard Maunsell, modified the Urie locomotives in the light of operational experience and increased the class strength to 74 locomotives. Maunsell and his Chief Draughtsman James Clayton incorporated several improvements, notably to the steam circuit and valve gear.
The new locomotives were built over several batches at Eastleigh and Glasgow, leading to the nicknames of "Eastleigh Arthurs", "Scotch Arthurs" and Scotchmen in service.[5] The class was subjected to smoke deflection experiments in 1926, becoming the first British class of steam locomotive to be fitted with smoke deflectors. Maunsell's successor, Oliver Bulleid, attempted to improve performance by altering exhaust arrangements. The locomotives continued operating with British Railways (BR) until the end of 1962. One example, 30777 Sir Lamiel, is preserved as part of the National Collection and can be seen on mainline railtours.
Background[]
Robert Urie completed his H15 class mixed-traffic 4-6-0 design in 1913 and the prototype was built in August 1914. It showed a marked improvement in performance over Dugald Drummond’s LSWR T14 class 4-6-0 when tested on local and express passenger trains. The introduction of ten H15 engines into service coincided with the outbreak of the First World War, which prevented construction of further class members. Despite the interruption caused by the conflict, Urie anticipated that peacetime increases in passenger traffic would necessitate longer trains from London to the south-west of England. Passenger loadings on the heavy boat trains to the London and South Western Railway’s (LSWR) ports of Portsmouth, Weymouth and Southampton had been increasing prior to the war, and was beginning to overcome the capabilities of the LSWR's passenger locomotive fleet. His response was to produce a modern, standard express passenger design similar to the H15.
Design and construction[]
For detailed information on numbering variations, see § Livery and numbering.
Trials undertaken in 1914 with the H15 class prototype had demonstrated to Urie that the basic design showed considerable speed potential on the Western section of the LSWR from Basingstoke westwards, and could form the basis of a powerful new class of 4-6-0 express passenger locomotive with larger 6 ft 7 in (2.01 m) driving wheels. The LSWR required such a locomotive, which would need to cope with increasing train loads on this long and arduous route to the West Country. The result was the N15 class design, completed by Urie in 1917. It incorporated features from the H15 class, including eight-wheel double bogie tenders with outside plate frames over the wheels and exposed Walschaerts valve gear. High running plates along the boiler were retained for ease of oiling and maintenance.
Despite the similarities, the N15 class represented a refinement of the H15 template. The cylinders were increased in size to 22 in × 28 in (560 mm × 710 mm) in diameter, the largest used on a British steam locomotive at that time. The substantial boiler design was also different from the parallel version used on the H15, and became the first tapered types to be constructed at Eastleigh Works. Contrary to boiler construction practices elsewhere where tapering began near the firebox, it was restricted to the front end of the N15's barrel to reduce the diameter of the smokebox, and consequently the weight carried by the front bogie. The design also featured Urie's design of narrow-diameter "stovepipe" chimney, a large dome cover on top of the boiler, and his "Eastleigh" superheater.
"Urie N15s"[]
The N15 design was approved by the LSWR management committee, though the order for construction was postponed until wartime control of raw materials was relaxed. Government approval was obtained in mid–1918, and Eastleigh Works began to produce the LSWR's first new locomotive class since 1914. The first locomotives, later known by crewmen as the "Urie N15s", were built in two ten-engine batches by the LSWR's Eastleigh Works between 1918–19 and 1922–23. Of the first batch, the prototype, No. 736 entered service on 31 August 1918, with four more appearing between September 1918 and April 1919. They shared a similar profile to Urie's H15 class with the use of flat-sided Drummond-style cabs with gently curving roofs. The double bogie tenders were outwardly similar in appearance to those used on the H15s, although strengthened during construction with extra internal bracing to hold 5,000 imperial gallons (22,700 l) of water. A shortage of copper delayed completion of Nos. 741–745, and the last of the batch emerged from Eastleigh in November 1919. After the running-in of Nos. 736–745 and an intensification of the LSWR timetable to the West Country, a second batch of ten was ordered in October 1921. They entered service over the period June 1922 – March 1923, and were numbered in the series 746–755.
At "Grouping" in January 1923, the LSWR became part of the new Southern Railway, whose Chief Mechanical Engineer was Richard Maunsell. Maunsell planned to introduce his own designs of express passenger locomotive, one of which was to become the future Lord Nelson class. Despite this, there was a short-term need to maintain existing services that required modification and expansion of Urie's N15 design.
Maunsell’s "Eastleigh Arthurs": Drummond rebuilds[]
Maunsell's projected design of express passenger locomotive was not ready for introduction during the summer timetable of 1925, so a third batch of ten N15s was ordered for construction at Eastleigh. This batch was part of an outstanding LSWR order to rebuild 15 of Drummond's unsuccessful 4-cylinder F13, G14 and P14 classes 4-6-0s into 2–cylinder H15 class locomotives. Only the five F13s were converted to H15s; the remaining ten G14 and P14s (Nos. 448–457, renumbered E448–E457) were rebuilt as N15s, implementing modifications to Urie's original design.
The modifications are attributed to Maunsell's Chief Draughtsman James Clayton, who had transferred to Ashford railway works in 1914 from Derby works. They were the result of cooperation between the South Eastern and Chatham Railway (SECR) and the Great Western Railway (GWR) when Maunsell was seconded to the Railway Executive Committee during the First World War. The aim was to create a series of standard freight and passenger locomotives for use throughout Britain, and meant that Clayton was privy to the latest GWR developments in steam design. These included streamlined steam passages, long-travel valves, the maximisation of power through reduced cylinder sizes and higher boiler pressure.
Maunsell initiated trials with Urie N15 No. 442 in 1924, and proved that better performance could be obtained by altering the steam circuit, valve travel and draughting arrangements. As a result, Clayton reduced the N15 cylinder diameter to 20.5 inches (520 mm) and replaced the safety valves with Ross pop valves set to 200 psi (1.38 MPa) boiler pressure. The Urie boiler was retained, though the Eastleigh superheater was replaced by a Maunsell type with 10 per cent greater superheating surface area. This was supplemented by a larger steam chest and an increased-diameter chimney casting specially designed for the rebuilds. It incorporated a rim and capuchon to control exhaust flow into the atmosphere. Valve events (the timing of valve movements with the piston) were also revised to promote efficient steam usage and the wheels were re-balanced to reduce hammerblow.
When rebuilding was complete, only the numbers, smokebox doors with centre tightening handles and the flat-sided cabs remained of the G14 and P14 classes. The rebuilds retained their distinctive Drummond "watercart" tenders, which were modified with the removal of the complex injector feedwater heating equipment. The "watercart" tenders were of 4,300 imp gal (19,500 l) water and 5.00 long tons (5.1 t) coal capacity. The ten rebuilds became the first members of the King Arthur class upon entering service.
"Scotch Arthurs"[]
As the Drummond G14 and P14 4-6-0s were rebuilt to the N15 specification at Eastleigh, a lack of production capacity due to repair and overhaul meant that Maunsell ordered a further batch of 20 locomotives from the North British Locomotive Company in 1924. The company had under-quoted to gain the contract, which meant that production of the batch was rushed. The necessity to maintain an intensive timetable on the Southern Railway's Western section prompted an increase of the order to 30 locomotives (Nos. E763–E792). Their construction in Glasgow would gain them the "Scotch Arthurs" nickname in service. They were all delivered to the Southern Railway by October 1925, and featured the front-end refinements used on the Drummond rebuilds.
The North British batch was built to the Southern's new composite loading gauge and differed from previous batches in having an Ashford-style cab based upon that used on the N class. Unlike the Drummond cab retained by Nos. 448–457 and E741–E755, the Ashford cab was of an all-steel construction and had a roof that was flush with the cab sides, allowing it to be used on gauge-restricted routes in the east of the network. It was inspired by the standard cab developed in 1904 by R. M. Deeley for the Midland Railway, and was one of a number of Midland features introduced by Clayton to the SECR and subsequently the Southern Railway. The smokebox door was revised to the Ashford pattern, which omitted the use of central tightening handles in favour of clamps around the circumference. The batch was fitted with the Urie-designed, North British-built 5,000 imp gal (22,700 l) capacity double-bogie tenders.
Maunsell's "Eastleigh Arthurs": second batch[]
With the "Scotch Arthurs" in service, the Southern Railway had an ample fleet of express passenger locomotives for its Western section routes. As part of a process of fleet standardisation, the Operating Department expressed a desire replace obsolescent locomotives on the Eastern and Central sections with the King Arthur class. In May 1925, a batch of 25 locomotives (Nos. E793–E817) based upon the Scotch Arthurs was ordered for construction at Eastleigh with smaller firebox grates and improved water heating surfaces. After the first 14 (Nos. E793–E806) were built, it was decided to discontinue construction in favour of Maunsell's new 4-cylinder Lord Nelson class design in June 1926.
The Operating Department intended to equip Nos. E793–E807 with six-wheel, 4,000 imp gal (18,200 l) capacity tenders for use on the former SECR lines of the Eastern section. These were to replace Scotch Arthurs Nos. E763–E772 on boat train duties. This was because the 5,000 imp gal (22,700 l) tenders attached to Nos. E763–E772 were better suited to the longer routes of the Western section. The final ten engines (Nos. E808–E817) were for the former LBSCR routes of the Central section, where short turntables restricted tender size to the 3,500 imp gal (15,900 l) Ashford variety used on the N class. After the order was changed to the Lord Nelson class design, 14 N class tenders were fitted to Nos. E793–E806 for use the Central section. The high draw-gear (the link between locomotive and tender) of the N class tenders necessitated modification to the frames beneath the cab.
Naming the locomotives[]
When the former Drummond G14 and P14 4-6-0s were rebuilt to Maunsell's N15 specification in February 1925, the Southern Railway decided to give names to all express passenger locomotives. Because of the railway's association with the West of England, the Public Relations Officer, John Elliot suggested that members of the N15 class should be named after characters and places associated with the legend of King Arthur. When Maunsell was told of the decision to name the locomotives, he replied: "Tell Sir Herbert [Walker] I have no objection, but I warn you, it won't make any difference to the working of the engines". Walker was the General Manager of the Southern Railway, who had told Elliot that Maunsell's permission was required. The first G14 to be rebuilt, No. E453, was given the first name and christened King Arthur. The Urie locomotives (hitherto referred as N15s rather than King Arthurs) were also given names connected with Arthurian legend and were referred to as "Urie Arthurs"; the Maunsell batches of N15s were nicknamed the "Eastleigh" and "Scotch Arthurs".
Accidents and incidents[]
- In 1940, No. 751 Etarre, No. 755 The Red Knight, No. 775 Sir Agravaine, and No. 776 Sir Galagars along with T14 No. 458 and N15X No. 2328 Hackworth suffered bomb damage during the air raid on Nine Elms shed. No. 458 was scrapped and the other engines were eventually repaired.
- On 16 August 1944, 806 Sir Galleron was damaged by a V-1 flying bomb whilst pulling a passenger train in Upchurch; eight people were killed. The locomotive was eventually repaired and put back into service.
- On 26 November 1947, locomotive No. 753 King Arthur was hauling a passenger train that was in a rear-end collision with another, the other being hauled by SR Lord Nelson Class 4-6-0 No. 860 Lord Hawke, at Farnborough, Hampshire due to a signalman's error. Two people were killed
- On 22 January 1955, locomotive No. 30783 Sir Gillemere collided with H15 No. 30485 at Bournemouth Central station after its driver misread signals. The locomotive was subsequently repaired; The H15 was condemned.
- On 18 September 1962, locomotive No. 30770 Sir Prianus was hauling a newspaper train that caught fire between Knowle Junction and Botley. Four of the five carriages were destoyed.
The Urie Arthurs[]
The Eastleigh Arthurs[]
The Scotch Arthurs[edit][]
| Image | BR No. | SR No. | SR Name | Builder | Built | Withdrawn | Notes |
| 30763 | 763 | Sir Bors de Ganis | North British Loco 23209 | May 1925 | October 1960 | ||
| 30764 | 764 | Sir Gawain | North British Loco 23210 | May 1925 | July 1961 | ||
| 30765 | 765 | Sir Gareth | North British Loco 23211 | May 1925 | September 1962 | ||
| 30766 | 766 | Sir Geraint | North British Loco 23212 | May 1925 | December 1958 | ||
| 30767 | 767 | Sir Valence | North British Loco 23213 | May 1925 | June 1959 | ||
| 30768 | 768 | Sir Balin | North British Loco 23214 | May 1925 | November 1961 | ||
| 30769 | 769 | Sir Balan | North British Loco 23215 | June 1925 | March 1960 | ||
| 30770 | 770 | Sir Prianius | North British Loco 23216 | June 1925 | November 1962 | This locomotive was the subject of a spelling mistake, as the Knight of the same name in the book Le Morte d'Arthur by Sir Thomas Malory was Sir Priamus. | |
| 30771 | 771 | Sir Sagramore | North British Loco 23217 | June 1925 | February 1961 | ||
| 30772 | 772 | Sir Percivale | North British Loco 23218 | June 1925 | September 1961 | ||
| 30773 | 773 | Sir Lavaine | North British Loco 23219 | June 1925 | February 1962 | ||
| 30774 | 774 | Sir Gaheris | North British Loco 23220 | June 1925 | January 1960 | ||
| 30775 | 775 | Sir Agravaine | North British Loco 23221 | June 1925 | February 1960 | ||
| 30776 | 776 | Sir Galagars | North British Loco 23222 | June 1925 | January 1959 | ||
| 30777 | 777 | Sir Lamiel | North British Loco 23223 | June 1925 | October 1961 | Preserved as part of the National Collection, under overhaul at the Great Central Railway. | |
| 30778 | 778 | Sir Pelleas | North British Loco 23224 | July 1925 | May 1959 | ||
| 30779 | 779 | Sir Colgrevance | North British Loco 23225 | July 1925 | July 1959 | ||
| 30780 | 780 | Sir Persant | North British Loco 23226 | July 1925 | July 1959 | ||
| 30781 | 781 | Sir Aglovale | North British Loco 23227 | August 1925 | May 1962 | ||
| 30782 | 782 | Sir Brian | North British Loco 23228 | July 1925 | September 1962 | ||
|
30783 | 783 | Sir Gillemere | North British Loco 23279 | August 1925 | March 1961 | |
| 30784 | 784 | Sir Nerovens | North British Loco 23280 | September 1925 | October 1959 | ||
| 30785 | 785 | Sir Mador de la Porte | North British Loco 23281 | September 1925 | October 1959 | ||
| 30786 | 786 | Sir Lionel | North British Loco 23282 | September 1925 | August 1959 | ||
| 30787 | 787 | Sir Menadeuke | North British Loco 23283 | September 1925 | February 1959 | ||
| 30788 | 788 | Sir Urre of the Mount | North British Loco 23284 | September 1925 | February 1962 | ||
| 30789 | 789 | Sir Guy | North British Loco 23285 | September 1925 | December 1959 | ||
| 30790 | 790 | Sir Villiars | North British Loco 23286 | September 1925 | November 1961 | ||
| 30791 | 791 | Sir Uwaine | North British Loco 23287 | September 1925 | May 1960 | ||
| 30792 | 792 | Sir Hervis de Revel | North British Loco 23288 | September 1925 | February 1959 |
Livery and numbering[]
LSWR and Southern Railway[]
Under LSWR ownership, the "Urie N15s" were painted in Urie's LSWR sage green livery for passenger locomotives. This was distinct from Drummond's sage green because it was more olive in colour, and yellowed with cleaning and weathering. Black and white lining decorated the boiler bands and borders of the sage green panels. The lettering was in gilt: the initials "LSWR" located on the side of the tender, the locomotive number on the cabside.
The first Southern livery continued that of the LSWR, though with primrose yellow transfers showing "SOUTHERN" and the locomotive number, placed on the tender. The lining separating the black border on tender and cab side panels was changed to yellow. Primrose yellow transfers, showing "SOUTHERN" and the locomotive number, were placed on the tender. An "E" prefix was located above the tender number (e.g. E749), denoting that the class was registered for maintenance at Eastleigh works. The gilt numerals on the cabside and tender rear were replaced by a cast oval plate with "Southern Railway" around the edge and the number located in the centre. Yellow numerals were painted onto the front buffer beam to ease identification. In February 1925 Maunsell developed a deeper green with black and white lining. This was applied to his new King Arthur class locomotives and the "Urie N15s" were similarly painted when overhauls were due. Wheels were olive-green with black tyres. From 1929 the "E" prefix was removed and the cast numerals on the tender rear were removed and replaced with yellow transfers (e.g. 749).
In May 1938, after Bulleid's appointment as CME, No. 749 Iseult was trialled in bright unlined light green with yellow-painted block numerals replacing the cast numberplates. The tender was given two designs of lettering, with "SOUTHERN" on one side and the initials "SR" on the other. The Board of Directors disapproved and Bulleid repainted the locomotive in darker malachite green with black and white lining (this would later be applied to his Pacifics). The legend "SOUTHERN" in block-lettering remained on the tender, though the number was relocated to the cabside on one side and the smoke deflector on the other. Both were painted in a light "sunshine yellow". No. 749 was returned to Maunsell's green livery.
Several variations of the Maunsell green, Urie sage green and Bulleid malachite green liveries were tried with black, white/black, and yellow lining, some sporting a green panel on the smoke deflectors. However, from 1942 to 1946, during the Second World War, members of the class under overhaul were turned out in unlined-black livery as a wartime economy measure, with green-shaded sunshine yellow lettering. The final Southern livery used from 1946 reverted to malachite green, with yellow/black lining, and sunshine yellow lettering. Some of the class (Nos. 782 and 800, Sir Brian and Sir Persant) did not receive this livery.
British Railways[]
British Railways gave the class the power classification of 5P after nationalisation in 1948. For the first 18 months the locomotives sported a transitional livery: Southern Railway malachite green with "BRITISH RAILWAYS" on the tender in sunshine yellow lettering. As each member of the class became due for a heavy general overhaul, they were repainted in the new standard British Railways express passenger livery of Brunswick green with orange and black lining from April 1949. Initially, the British Railways "Cycling Lion" crest was located on the tender, replaced from the 1957 by the later "Ferret and Dartboard" crest.
Numbering was initially a continuation of the Southern Railway system, though an 'S' prefix was added to denote a pre-nationalisation locomotive, so that No. 448 would become No. s448. As each locomotive became due for overhaul and received its new livery, the numbering was changed to the British Railways standard numbering system, in the series 30448–30457 for the first ten and 30736–30806 for the rest.
Operational assessment and preservation[]
For class details and current status of the preserved locomotive, see List of King Arthur class locomotives.
After the poor steaming of the Urie batch was addressed, the class proved popular amongst crews, mechanically reliable and capable of high speeds. However, their heavy hammerblow at speed meant that they were prone to rough riding and instability. The two Maunsell batches with their streamlined steam passages and better draughting arrangements were superior in performance, and were a popular choice when Bulleid's locomotives were unavailable. Their use of standard parts considerably eased maintenance, and the fitting of different tender and cab sizes meant few operational restrictions for the class on mainline routes. The class gave many years of service, and were noted for their ability to "do the job". The electrification of the Eastern and Central sections and the increasing number of Bulleid Pacifics in service meant the lack of a suitable role for the class under British Railways ownership. In spite of the reduction in work, high mileages were obtained with No. 30745 Tintagel achieving 1,464,032 miles (2,356,131 km) in service.
The decision to preserve a member of the class was made in November 1960. It was first intended to preserve the King Arthur class doyen No. 30453 King Arthur, and it was stored for a time after withdrawal in 1961 pending restoration to museum condition. However, it was decided to restore the preserved locomotive to as-built condition, and the lack of a suitable Drummond "watercart" tender precluded this consideration. No. 30453 was subsequently scrapped and it was decided to preserve one of the North British-built batch, No. 30777 Sir Lamiel, withdrawn in October 1961, instead. Sir Lamiel was named after a character in Thomas Malory's Le Morte d'Arthur, Sir Lamiel of Cardiff. This locomotive was restored to Maunsell livery as No. E777, and became part of the National Collection. It was restored to the later British Railways livery in 2003. As of 2022, 30777 is under overhaul to service.
Models[]
Hornby Railways manufacture a model of the N15 in OO gauge.
In fiction[]
In Thomas & Friends, the locomotive's basis was used for Merlin in the animated film, Journey Beyond Sodor.



