SECR K and SR K1 classes
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The SECR K class was a type of
2-6-4 Under the Whyte notation for the classification of steam locomotives, a locomotive has two leading wheels, six coupled driving wheels and four trailing wheels. This arrangement is commonly called Adriatic. Overview With only a few known except ...
tank locomotive A tank locomotive or tank engine is a steam locomotive that carries its water in one or more on-board water tanks, instead of a more traditional tender. Most tank engines also have bunkers (or fuel tanks) to hold fuel; in a tender-tank locom ...
designed in 1914 by
Richard Maunsell Richard Edward Lloyd Maunsell (pronounced "Mansell") (26 May 1868 – 7 March 1944) held the post of chief mechanical engineer (CME) of the South Eastern and Chatham Railway from 1913 until the 1923 Grouping and then the post of CME of the ...
for express passenger duties on the
South Eastern and Chatham Railway The South Eastern and Chatham Railway Companies Joint Management Committee (SE&CRCJMC),Awdry (1990), page 199 known as the South Eastern and Chatham Railway (SE&CR), was a working union of two neighbouring rival railways, the South Easter ...
(SECR), which operated between London and south-east England. The Southern Railway (SR) K1 class was a three-cylinder variant of the K class, designed in 1925 to suit a narrower
loading gauge A loading gauge is a diagram or physical structure that defines the maximum height and width dimensions in railway vehicles and their loads. Their purpose is to ensure that rail vehicles can pass safely through tunnels and under bridges, and ke ...
. They were among the first non-
Great Western Railway The Great Western Railway (GWR) was a British railway company that linked London with the southwest, west and West Midlands of England and most of Wales. It was founded in 1833, received its enabling Act of Parliament on 31 August 1835 and ran ...
(GWR) types to use and improve upon the basic design principles of power and standardisation established by GWR
Chief Mechanical Engineer Chief mechanical engineer and locomotive superintendent are titles applied by British, Australian, and New Zealand railway companies to the person ultimately responsible to the board of the company for the building and maintaining of the locomotive ...
(CME)
George Jackson Churchward George Jackson Churchward (31 January 1857 – 19 December 1933) was an English railway engineer, and was chief mechanical engineer of the Great Western Railway (GWR) in the United Kingdom from 1902 to 1922. Early life Churchward was born at ...
. The locomotives were based on the GWR 4300 class, improved by the
Midland Railway The Midland Railway (MR) was a railway company in the United Kingdom from 1844. The Midland was one of the largest railway companies in Britain in the early 20th century, and the largest employer in Derby, where it had its headquarters. It am ...
's ideals of simplicity and ease of maintenance.Scott-Morgan (2002), p. 18 The K class was designed to be mechanically similar to the SECR N class 2-6-0 mixed-traffic locomotives. The class was one of the earliest to use the 2-6-4 wheel arrangement in Britain.Casserley (1966), p. 436 Production began towards the end of the
First World War World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...
, and the prototype rolled out of
Ashford Works Ashford railway works was in the town of Ashford in the county of Kent in England. History South Eastern Railway Ashford locomotive works was built by the South Eastern Railway on a new site in 1847, replacing an earlier locomotive repair fa ...
three years after design work was completed due to wartime production constraints. The class replaced obsolete
4-4-0 4-4-0 is a locomotive type with a classification that uses the Whyte notation for the classification of steam locomotives by wheel arrangement and represents the arrangement: four leading wheels on two axles (usually in a leading bogie), four po ...
passenger locomotives in an SECR fleet standardisation programme. Twenty-one locomotives were built: twenty K class (two cylinders) and one K1 class (three cylinders), the first in 1917 and the remainder between 1925 and 1926. They operated over the Eastern section of the Southern Railway network and were given the names of rivers, being referred as the River class from 1925. Crews referred to the K and K1 classes as "Rolling Rivers" because of their instability when travelling at speed. They were rebuilt as 2-cylinder SR U class and 3-cylinder SR U1 class 2-6-0s (respectively) following a railway accident at Sevenoaks, Kent in 1927. They continued in service with
British Railways British Railways (BR), which from 1965 traded as British Rail, was a state-owned company that operated most of the overground rail transport in Great Britain from 1948 to 1997. It was formed from the nationalisation of the Big Four British rai ...
(BR) until the last was withdrawn in 1966. One K class rebuild (No. 31806) is preserved on the Swanage Railway in Dorset and still operational today.


Background

Three factors dictated the type of locomotive that could operate on the
South Eastern and Chatham Railway The South Eastern and Chatham Railway Companies Joint Management Committee (SE&CRCJMC),Awdry (1990), page 199 known as the South Eastern and Chatham Railway (SE&CR), was a working union of two neighbouring rival railways, the South Easter ...
(SECR): the heavy passenger train loadings; the poor track quality; and the weak, lightly built bridges. On the lines of the former
London, Chatham and Dover Railway The London, Chatham and Dover Railway (LCDR or LC&DR) was a railway company in south-eastern England created on 1 August 1859, when the East Kent Railway was given parliamentary approval to change its name. Its lines ran through London and nor ...
(LCDR) – inherited by the SECR in 1899 – beach pebbles had been used for
ballast Ballast is material that is used to provide stability to a vehicle or structure. Ballast, other than cargo, may be placed in a vehicle, often a ship or the gondola of a balloon or airship, to provide stability. A compartment within a boat, ship, ...
instead of conventional ballast, which has irregular shapes that lock together to keep the track in place. These economies in construction meant that only locomotives with low
axle loading An axle or axletree is a central shaft for a rotation, rotating wheel and axle, wheel or gear. On wheeled vehicles, the axle may be fixed to the wheels, rotating with them, or fixed to the vehicle, with the wheels rotating around the axle. In ...
s could operate safely over the track. The SECR was therefore unable to follow a coherent strategy to reduce the number of locomotive types inherited from the two constituent railways. Despite increased passenger and freight traffic between and the
Kent Kent is a county in South East England and one of the home counties. It borders Greater London to the north-west, Surrey to the west and East Sussex to the south-west, and Essex to the north across the estuary of the River Thames; it faces ...
ish coast during the first decades of the 20th century, the Operating Department had to use mismatched classes of underpowered and obsolete
4-4-0 4-4-0 is a locomotive type with a classification that uses the Whyte notation for the classification of steam locomotives by wheel arrangement and represents the arrangement: four leading wheels on two axles (usually in a leading bogie), four po ...
and
0-6-0 Under the Whyte notation for the classification of steam locomotives, represents the wheel arrangement of no leading wheels, six powered and coupled driving wheels on three axles and no trailing wheels. This was the most common wheel arrangemen ...
locomotives, which could operate within the restrictions imposed by the infrastructure.Whitehouse & Thomas (2002), p. 50 This resulted in frequent
double-heading In railroad terminology, double heading indicates the use of two locomotives at the front of a train, each operated individually by its own crew. The practice of triple-heading involves the use of three locomotives. The practice of multi-headin ...
, adding to operational costs.Whitehouse & Thomas (2002), p. 51 Richard Maunsell was appointed CME of the SECR in 1913, following the enforced retirement of
Harry Wainwright Harry Smith Wainwright (16 November 1864 – 19 September 1925) was an English railway engineer, and was the Locomotive, Carriage and Wagon Superintendent of the South Eastern and Chatham Railway from 1899 to 1913. He is best known for a s ...
, who had left a range of competent but unspectacular locomotive classes that struggled to cope with the increased train lengths and loadings.Whitehouse & Thomas (2002), p. 49 Maunsell reviewed the situation and planned to introduce six standard classes – using only two boiler designs – which would work the entire traffic of the railway.Bradley (1980), pp. 66–67 The first of these was the N class 2-6-0, which gave the SECR a capable
mixed-traffic locomotive A locomotive or engine is a rail transport vehicle that provides the motive power for a train. If a locomotive is capable of carrying a payload, it is usually rather referred to as a multiple unit, motor coach, railcar or power car; the ...
. For the express passenger design that could cope with the heavy
boat train A boat train is a passenger train operating to a port for the specific purpose of making connection with a passenger ship, such as a ferry, ocean liner, or cruise ship. Through ticketing is normally available. __NOTOC__ Notable named boat trains ...
s, Maunsell wanted to enlarge the existing L class
4-4-0 4-4-0 is a locomotive type with a classification that uses the Whyte notation for the classification of steam locomotives by wheel arrangement and represents the arrangement: four leading wheels on two axles (usually in a leading bogie), four po ...
with
Walschaerts valve gear The Walschaerts valve gear is a type of valve gear used to regulate the flow of steam to the pistons in steam locomotives, invented by Belgium, Belgian railway mechanical engineering, engineer Egide Walschaerts in 1844. The gear is sometimes name ...
and an enlarged
superheater A superheater is a device used to convert saturated steam or wet steam into superheated steam or dry steam. Superheated steam is used in steam turbines for electricity generation, steam engines, and in processes such as steam reforming. There ar ...
, but this design would have resulted in a too heavy
axle loading An axle or axletree is a central shaft for a rotation, rotating wheel and axle, wheel or gear. On wheeled vehicles, the axle may be fixed to the wheels, rotating with them, or fixed to the vehicle, with the wheels rotating around the axle. In ...
. Maunsell's newly recruited assistants, G.H. Pearson and
Harold Holcroft Harold Holcroft (12 February 1882 – 15 February 1973) was an English railway and mechanical engineer who worked for the Great Western Railway (GWR), the South Eastern and Chatham Railway (SECR) and the Southern Railway (SR). At the GWR, Holcr ...
from the
Great Western Railway The Great Western Railway (GWR) was a British railway company that linked London with the southwest, west and West Midlands of England and most of Wales. It was founded in 1833, received its enabling Act of Parliament on 31 August 1835 and ran ...
at
Swindon Swindon () is a town and unitary authority with Borough status in the United Kingdom, borough status in Wiltshire, England. As of the 2021 Census, the population of Swindon was 201,669, making it the largest town in the county. The Swindon un ...
and James Clayton from the
Midland Railway The Midland Railway (MR) was a railway company in the United Kingdom from 1844. The Midland was one of the largest railway companies in Britain in the early 20th century, and the largest employer in Derby, where it had its headquarters. It am ...
at
Derby Derby ( ) is a city and unitary authority area in Derbyshire, England. It lies on the banks of the River Derwent in the south of Derbyshire, which is in the East Midlands Region. It was traditionally the county town of Derbyshire. Derby gai ...
, had recently been involved in the design of large passenger tank engines and persuaded him to use the
2-6-4 Under the Whyte notation for the classification of steam locomotives, a locomotive has two leading wheels, six coupled driving wheels and four trailing wheels. This arrangement is commonly called Adriatic. Overview With only a few known except ...
wheel arrangement In rail transport, a wheel arrangement or wheel configuration is a system of classifying the way in which wheels are distributed under a locomotive. Several notations exist to describe the wheel assemblies of a locomotive by type, position, and c ...
, which would allow the class to operate at high speeds on the poor-quality track in north Kent.


Design and construction

The 2-6-4 wheel arrangement was not in common use in Great Britain at this time, as many railway companies operated routes that required locomotives with greater fuel capacity, or short branch lines that necessitated smaller locomotives. The 2-6-4 tank engine design had only been used once before for
standard gauge A standard-gauge railway is a railway with a track gauge of . The standard gauge is also called Stephenson gauge (after George Stephenson), International gauge, UIC gauge, uniform gauge, normal gauge and European gauge in Europe, and SGR in Ea ...
locomotives in Britain, on the
Great Central Railway The Great Central Railway in England was formed when the Manchester, Sheffield and Lincolnshire Railway changed its name in 1897, anticipating the opening in 1899 of its London Extension. On 1 January 1923, the company was grouped into the ...
's 1B class freight locomotives of 1914.Bradley (1961), p. 52 However, the configuration was ideal for the SECR, because of its shorter mainlines, and allowed for a long wheelbase with a leading axle to permit greater stability at speed on track curves. The tightness of the curves on the former LCDR mainlines had constrained the size of locomotives operating on the SECR, as they had been hastily erected during the nineteenth century to compete with those of the South Eastern Railway (SER). The longer locomotive could also accommodate a larger
boiler A boiler is a closed vessel in which fluid (generally water) is heated. The fluid does not necessarily boil. The heated or vaporized fluid exits the boiler for use in various processes or heating applications, including water heating, central h ...
than a 4-4-0, giving sufficient power to avoid double-heading of locomotives on heavier trains. The K class design used a "
Bissel bogie A Bissell or Bissel truck (also Bissel bogie or Pony truck) is a single-axle bogie which pivots towards the centre of a steam locomotive to enable it to negotiate curves more easily. Invented in 1857 by and usually then known as a ''pony truck'' ...
" leading axle and a plain trailing
bogie A bogie ( ) (in some senses called a truck in North American English) is a chassis or framework that carries a wheelset, attached to a vehicle—a modular subassembly of wheels and axles. Bogies take various forms in various modes of transp ...
. The trailing bogie permitted the use of a large coal bunker that was capable of sustaining the locomotive over the run between London Charing Cross and , and side water tanks of capacity were used, negating the need for a tender. The coupled wheelbase between the rear and centre driving wheels was reduced from that used on the mechanically identical N class to to accommodate the bogie.Bradley (1961), p. 53 The cab was fully enclosed, although the set of four small front
spectacle plate In general, spectacle refers to an event that is memorable for the appearance it creates. Derived in Middle English from c. 1340 as "specially prepared or arranged display" it was borrowed from Old French ''spectacle'', itself a reflection of the ...
s (the windows on the front face of the cab for forward visibility) were the same as those used on the N class. The K class was designed by Maunsell's team in 1914 as part of his proposed standardisation programme following the N class, but the designs were not shown to the railway directors until early 1915 to enable all six designs to be shown at once. The design incorporated the principles of power and reliability established by
George Churchward George Jackson Churchward (31 January 1857 – 19 December 1933) was an English railway engineer, and was chief mechanical engineer of the Great Western Railway (GWR) in the United Kingdom from 1902 to 1922. Early life Churchward was born at ...
, using a
Belpaire firebox The Belpaire firebox is a type of firebox used on steam locomotives. It was invented by Alfred Belpaire of Belgium in 1864. Today it generally refers to the shape of the outer shell of the firebox which is approximately flat at the top and sq ...
that sloped downwards towards the cab instead of a round-topped version, a regulator located in the
smokebox A smokebox is one of the major basic parts of a steam locomotive exhaust system. Smoke and hot gases pass from the firebox through tubes where they pass heat to the surrounding water in the boiler. The smoke then enters the smokebox, and is e ...
, long-travel valves for free running at high speeds, a sharply tapered and domeless boiler, and a right-hand driving position.Middlemass (1990), pp. 148–154 The inclusion of these features is attributed to Holcroft, Maunsell's personal assistant, who had worked on the GWR 4300 class and the N class.Haresnape (1983), pp. 34–36 James Clayton, Maunsell's Chief Locomotive Draughtsman, brought simpler and more functional
Midland Railway The Midland Railway (MR) was a railway company in the United Kingdom from 1844. The Midland was one of the largest railway companies in Britain in the early 20th century, and the largest employer in Derby, where it had its headquarters. It am ...
influences to the design, such as the shape of the cab and the drumhead-type smokebox, which sat on a saddle that was of wider diameter than the fully lagged and clad boiler.Rowledge (1976), p. 8 The latter was fitted with Ross pop
safety valve A safety valve is a valve that acts as a fail-safe. An example of safety valve is a pressure relief valve (PRV), which automatically releases a substance from a boiler, pressure vessel, or other system, when the pressure or temperature exceeds ...
s and pressed to . Other innovations by Maunsell's team included greater
superheating In thermodynamics, superheating (sometimes referred to as boiling retardation, or boiling delay) is the phenomenon in which a liquid is heated to a temperature higher than its boiling point, without boiling. This is a so-called ''metastable state ...
surface area, locating the boiler water
top feed A spinning top, or simply a top, is a toy with a squat body and a sharp point at the bottom, designed to be rotation, spun on its vertical Axis of rotation, axis, balancing on the tip due to the gyroscopic effect. Once set in motion, a top will ...
inside a dome-like cover with external clackboxes and water feed pipes mounted on either side, outside Walschaerts valve gear, and parts that could be shared with similar locomotive classes to reduce maintenance costs.Clarke (February 2008), p. 38 The firebox was narrower towards the rear and featured a continuously sloping grate, whilst the ashpan was fitted with front and rear damper doors, the latter adjusted to clear the rear driving axle. The lower part of the coal bunker incorporated a water tank of capacity. This was connected to two side tanks by two rectangular pipes on either side of the locomotive that also formed supports for the cab
footplate A footplate provides the structure on which a locomotive driver and fireman stand in the cab to operate a British or continental European steam locomotive. It comprises a large metal plate that rests on top of the locomotive frame, usually it is ...
.Rowledge (1976), p. 10


K class

In January 1915 Maunsell received authority to build six examples, but, as with the N class, production was delayed due to the use of the
Ashford works Ashford railway works was in the town of Ashford in the county of Kent in England. History South Eastern Railway Ashford locomotive works was built by the South Eastern Railway on a new site in 1847, replacing an earlier locomotive repair fa ...
for wartime armaments manufacture. Assembly began in 1917 and the first, No. 790, emerged in July of that year. It was based at Bricklayers Arms depot, preceding the earlier N class design into service by one month.''Railway Engineer'' (1923), pp. 140–143 Further construction was deferred until after Ashford had caught up with the maintenance backlog caused by the war. Ten more locomotives were ordered by the SECR from Ashford works in June 1920, and to speed delivery the construction of frames, cylinders and side tanks was subcontracted to the
Royal Arsenal The Royal Arsenal, Woolwich is an establishment on the south bank of the River Thames in Woolwich in south-east London, England, that was used for the manufacture of armaments and ammunition, proofing, and explosives research for the Britis ...
at
Woolwich Woolwich () is a district in southeast London, England, within the Royal Borough of Greenwich. The district's location on the River Thames led to its status as an important naval, military and industrial area; a role that was maintained throu ...
. However, further severe delays at Ashford caused by the backlog of repair work meant that the boilers had to be supplied by the
North British Locomotive Company The North British Locomotive Company (NBL, NB Loco or North British) was created in 1903 through the merger of three Glasgow locomotive manufacturing companies; Sharp, Stewart and Company (Atlas Works), Neilson, Reid and Company (Hyde Park Wor ...
.Bradley (1980), p. 70 Construction of these locomotives had not begun by 1 January 1923, when the
Railways Act 1921 The Railways Act 1921 (c. 55), also known as the Grouping Act, was an Act of Parliament enacted by the British government and intended to stem the losses being made by many of the country's 120 railway companies, by "grouping" them into four la ...
merged the SECR with other railways in southern England to form the Southern Railway. Maunsell was appointed CME of the newly formed Southern Railway in 1923, and inherited the 1920 SECR order for ten K class locomotives. The order was still outstanding in 1924, although most of the component parts had been made. On 14 January 1925, Maunsell ordered No. 790 to be overhauled and trialled on the Central section.Holcroft (1965), pp. 145–147 As the locomotive proved suitable for the operating conditions of this section, the Southern Railway's Locomotive Committee proceeded with the assembly of the K class parts using outside contractors. Nine sets of parts (Nos. A791–A799) were conveyed to
Armstrong Whitworth Sir W G Armstrong Whitworth & Co Ltd was a major British manufacturing company of the early years of the 20th century. With headquarters in Elswick, Newcastle upon Tyne, Armstrong Whitworth built armaments, ships, locomotives, automobiles and a ...
for assembly and the finished locomotives delivered in May and June 1925. These were dual-fitted with
vacuum A vacuum is a space devoid of matter. The word is derived from the Latin adjective ''vacuus'' for "vacant" or "void". An approximation to such vacuum is a region with a gaseous pressure much less than atmospheric pressure. Physicists often dis ...
and Westinghouse (air) brakes for use with the former
London, Brighton and South Coast Railway The London, Brighton and South Coast Railway (LB&SCR; known also as the Brighton line, the Brighton Railway or the Brighton) was a railway company in the United Kingdom from 1846 to 1922. Its territory formed a rough triangle, with London at its ...
(LBSCR) rolling stock on the Central section. Other differences from the prototype included the relocation of the regulator to the dome and an increase in superheater area. The tenth set of parts was retained by Ashford and used for the first member of the K1 class later that year. In May 1925 Maunsell ordered a further ten locomotives from
Brighton works Brighton railway works (also known as Brighton locomotive works, or just the Brighton works) was one of the earliest railway-owned locomotive repair works, founded in 1840 by the London and Brighton Railway in Brighton, England, and thus pre-da ...
(Nos. A800–A809), which only had vacuum brakes for the SECR stock on the Eastern section. They were delivered between July and December 1926. This group had modified suspension on the bogie and leading axle, in an attempt to address complaints from the crews of rough riding experienced with earlier members of the class. A further 20 members of the class were ordered in March 1926 (ten each from Ashford and Brighton works), despite strong reservations expressed by the Operating Department concerning "the wisdom or desirability of placing so many large passenger tanks in service".Bradley (1980), p. 71 These were allocated the numbers A610–A629, and work had begun on building the frames and cylinders when the order was cancelled following an accident at Sevenoaks in 1927 involving locomotive No. A800. These numbers were later allocated to the first production batch of U class locomotives.


K1 class

In August 1919, a proposal was put to the SECR's Locomotive, Carriage and Wagon Committee for 2 and 3-cylinder tank engines of
2-8-0 Under the Whyte notation for the classification of steam locomotives, represents the wheel arrangement of two leading wheels on one axle, usually in a leading truck, eight powered and coupled driving wheels on four axles, and no trailing wheels. ...
wheel arrangement for heavy shunting of freight wagons.Rowledge (1976), p. 7 They were to use the same boiler as the K and N classes and the general layout was similar to designs used by the GWR in South Wales. Nothing came of this proposal because of other commitments and the absorption of the SECR into the Southern Railway. In 1922, Holcroft suggested that 3-cylinder 2-6-0 tender locomotives with driving wheels should be built instead of tank locomotives. Despite the benefit of a greater operational range, Holcroft's immediate superior, Clayton, refused to pass this suggestion on to Maunsell. The 3-cylinder principle was therefore applied to the K class. At the Southern Railway's January 1925 Locomotive Committee meeting, when it was decided to use outside contractors to build the K class, Maunsell received authority to retain one set of parts at Ashford works to construct a prototype 3-cylinder 2-6-4 tank. The modification was based upon that used on N class No. 822 to produce a 3-cylinder locomotive in 1922, although it retained the driving wheels and shorter wheelbase of the K class. The modification was the inclusion of an additional (inside) cylinder between the frames, and a crank axle was fitted to the middle driving wheels. The axle was connected to the inside cylinder assembly by a
connecting rod A connecting rod, also called a 'con rod', is the part of a piston engine which connects the piston to the crankshaft. Together with the crank, the connecting rod converts the reciprocating motion of the piston into the rotation of the cranksh ...
inclined at 1 in 8 to clear the front driving axle.Rowledge (1976), p. 11 This arrangement was supplemented by two smaller-diameter outside cylinders with bore (compared to the cylinders of the K class), and a greater chimney diameter. The resulting prototype 3-cylinder "K1" was narrower than the K class and hence could work on routes with restricted
loading gauge A loading gauge is a diagram or physical structure that defines the maximum height and width dimensions in railway vehicles and their loads. Their purpose is to ensure that rail vehicles can pass safely through tunnels and under bridges, and ke ...
. As with No. 822, this locomotive used Holcroft's derivative of the Gresley conjugated valve gear to drive the inside cylinder. To accommodate this, the boiler had to be raised by above the inside gear, raising the centre of gravity on the locomotive. The main visual difference between the K and K1 classes was at the front end: the K1 incorporated a vertical metal cover above the front buffer beam to protect the third cylinder and associated Holcroft valve gear assembly from the elements.Clarke (February 2008), p. 40 It also featured a new cab design with redesigned single front spectacle plates, and a pair of substantially constructed steps were fitted behind both outside cylinders to provide access to the running plate. The lack of a middle cylinder on the K class locomotives had allowed the provision of a footplate that curved from the buffers to the water tanks. The K1 prototype emerged from Ashford works as No. A890, and underwent trials from 1 December 1925 before entering regular service.Reynolds (1943), pp. 155–156 Only one locomotive of the K1 class was built; plans to build a further ten (Nos. A891-A900) alongside a batch of five N1 class 2-6-0s were cancelled after the Sevenoaks accident in August 1927.Rowledge (1976), p. 22 Following rebuilding as a 2-6-0 tender locomotive in 1928, No. A890 was reclassified U1 and was the forerunner of twenty more basically similar locomotives built in 1931.


K and K1 class construction history


Naming the locomotives

The K class prototype operated without a name until 1925, when the Southern Railway's publicity department decided to name all express passenger locomotives. The locomotives constructed from 1925 were named after rivers found within the Southern Railway's operating area, and the class became known collectively as the River class.Burridge (1975), p. 48 The first-completed Southern Railway K class No. A791 was named ''River Adur'' whilst the former SECR prototype was given the name ''River Avon''; names were also allocated to the cancelled 1926 batch of locomotives.Burridge (1975), p. 49 The K1 class locomotive No. A890 was named ''River Frome''. The names were displayed on a rectangular brass nameplate fitted to the water tank sides.


Operational details

The K class was intended to haul the SECR's Kent expresses, and was trialled between Charing Cross, , and . A trial non-stop run between and by No. 790 pulling a train of had proved the water capacity of the side tanks to be insufficient for such runs.Holcroft (1965), p. 147 No. 790 was also tested on fast Cannon Street, and Tonbridge trains during the spring of 1922, although rough riding between the latter two stations meant slower speeds over that part of route on subsequent runs.Rowledge (1976), p. 25 The Southern Railway's motive power re-organisation following the Grouping of 1923 expanded the class for operations over the Central section. The Westinghouse-fitted Armstrong Whitworth batch was used on the air-braked and expresses and regular passenger service trains to
Portsmouth Portsmouth ( ) is a port and city in the ceremonial county of Hampshire in southern England. The city of Portsmouth has been a unitary authority since 1 April 1997 and is administered by Portsmouth City Council. Portsmouth is the most dens ...
. The vacuum-braked Brighton batch was run-in on the Portsmouth route in preparation for operating the Redhill–Reading line, the class regularly hauling the daily
Birkenhead Birkenhead (; cy, Penbedw) is a town in the Metropolitan Borough of Wirral, Merseyside, England; historically, it was part of Cheshire until 1974. The town is on the Wirral Peninsula, along the south bank of the River Mersey, opposite Liver ...
–Dover through train. The K1 was mainly rostered to haul the early evening express from Cannon Street to Dover Marine.


Performance of the tank locomotives

The K class proved successful on well-maintained track. It was capable of high speeds on express passenger duties, although their use was limited by the lower storage capacity of tank locomotives, which meant the K and K1 classes were prone to water shortages on the long Kent Coast routes, and precluded them from working many of the former
London and South Western Railway The London and South Western Railway (LSWR, sometimes written L&SWR) was a railway company in England from 1838 to 1922. Originating as the London and Southampton Railway, its network extended to Dorchester and Weymouth, to Salisbury, Exeter ...
(LSWR) routes west of London. The need to save weight meant that compromises were made in some aspects of the design. The boiler size was constrained by the SECR's axle-loading restrictions, with the result that the design's full steaming potential was not realised. The failure to capitalise upon a larger boiler would also affect Maunsell's subsequent 2-6-0 classes, as they were given the same boiler despite their lower axle-loadings. On the Southern Railway's Central and Eastern sections, crews complained that the locomotives rolled heavily and unpredictably on the cheaply laid track of the former SECR and LBSCR networks, leading to their nickname, "Rolling Rivers". The rolling was in part caused by the type of coil suspension and steadying springs used on the Bissel truck and bogie axles, which caused adverse springing on poor track.Rowledge (1976), p. 48 These were modified in later batches, with limited success.Rowledge (1976), p. 49 The rough-riding was also attributed to the frames, which were of insubstantial construction to save weight. The bracing proved incapable of counteracting the stresses applied to the frames when travelling at speed and caused excessive vibration on the footplate at higher outputs. The K1 prototype was slightly faster and more powerful than the K class, and gave a smoother ride at low speeds.Boocock (2010), p. 87 It was also found to have a wider route availability due to the smaller outside cylinders. However, the Holcroft valve gear proved to be difficult to maintain in everyday service. This locomotive was also noted for particularly poor riding characteristics at high speed, derailing twice in 1927.Clarke (March 2008), p. 55 The first derailment occurred at , near
Maidstone Maidstone is the largest Town status in the United Kingdom, town in Kent, England, of which it is the county town. Maidstone is historically important and lies 32 miles (51 km) east-south-east of London. The River Medway runs through the c ...
on 31 March, when the flanges of the lead coupled wheel mounted the rails at . The second derailment was at on 20 August, when the lead driving wheel mounted and completely dropped off the rails at , derailing the train and causing serious damage to the track. These derailments were attributed to the slightly higher centre of gravity of the boiler on the K1.Bradley (1961), p. 54 Although the official reports of these accidents blamed the poor quality of the track, a group of directors sought to have both classes banned from use on passenger services, but were overruled by the Southern Railway's Chairman of the Board of Directors,
Everard Baring Brigadier-General the Honourable Everard Baring (5 December 1865 — 7 May 1932) was a British Army officer and Chairman of the Southern Railway. Background early life Baring was born in Kingston, Surrey, one of ten children of Edward Char ...
on grounds of cost.Bradley (1980), p. 117


Accidents and incidents

*In March 1927, locomotive No. 890 ''River Frome'' was hauling a train which derailed at
Wrotham Wrotham ( ) is a village on the Pilgrims' Way in Kent, England, at the foot of the North Downs. It is north of Borough Green and approximately east of Sevenoaks. It is between the M20 and M26 motorways. History The name first occurs as ''U ...
,
Kent Kent is a county in South East England and one of the home counties. It borders Greater London to the north-west, Surrey to the west and East Sussex to the south-west, and Essex to the north across the estuary of the River Thames; it faces ...
. *On 2 August 1927, Locomotive No. 800 ''River Cray'' was derailed at
Maidstone Maidstone is the largest Town status in the United Kingdom, town in Kent, England, of which it is the county town. Maidstone is historically important and lies 32 miles (51 km) east-south-east of London. The River Medway runs through the c ...
, Kent. *On 20 August 1927, locomotive No. 890 ''River Frome'' was hauling a passenger train which was derailed at
Bearsted Bearsted ( , ) is a village and civil parishes in England, civil parish with railway station in mid-Kent, England, two miles (3.2 km) east of Maidstone town centre. Geography The village was historically concentrated around Church Lane a ...
, Kent. The cause was attributed to track defects. The locomotive was repaired and re-entered service on 23 August. It was involved in a serious accident the next day.


Sevenoaks disaster

The K and K1 classes suffered from stability problems when travelling at speed over points and curves. The locomotive would initially roll (briefly lean heavily) to one side, followed by several further rolls of gradually reducing amplitude, combined with a side-slipping movement that caused the driving wheels to mount the rails. Several minor derailments of members of the class were followed by the serious derailment of No. A800 ''River Cray'' at Sevenoaks,
Kent Kent is a county in South East England and one of the home counties. It borders Greater London to the north-west, Surrey to the west and East Sussex to the south-west, and Essex to the north across the estuary of the River Thames; it faces ...
, in August 1927, caused by a combination of a surge in the water tanks and the flanges of the locomotive's lead driving wheels mounting the rail at speed due to poor quality track-work.Railways Archive (2004
Ministry of Transport, Railway Accidents
(PDF copy of the original inquiry report for the Sevenoaks Railway Accident), Retrieved 6 January 2010
The locomotive was hauling a Cannon Street to express with a Pullman carriage when the leading driving wheels derailed at over
catch points Catch points and trap points are types of turnout which act as railway safety devices. Both work by guiding railway carriages and trucks from a dangerous route onto a separate, safer track. Catch points are used to derail vehicles which are ou ...
in a
cutting Cutting is the separation or opening of a physical object, into two or more portions, through the application of an acutely directed force. Implements commonly used for wikt:cut, cutting are the knife and saw, or in medicine and science the scal ...
. Several carriages were flung against a road bridge, injuring 40 and killing 13 passengers. In the days following the accident, two K and K1 class engines were trialled on the
London and North Eastern Railway The London and North Eastern Railway (LNER) was the second largest (after LMS) of the " Big Four" railway companies created by the Railways Act 1921 in Britain. It operated from 1 January 1923 until nationalisation on 1 January 1948. At th ...
's (LNER)
Great Northern Great Northern may refer to: Transport * One of a number of railways; see Great Northern Railway (disambiguation). * Great Northern Railway (U.S.), a defunct American transcontinental railroad and major predecessor of the BNSF Railway. * Great ...
mainline under the supervision of that company's CME,
Nigel Gresley Sir Herbert Nigel Gresley (19 June 1876 – 5 April 1941) was a British railway engineer. He was one of Britain's most famous steam locomotive engineers, who rose to become Chief Mechanical Engineer (CME) of the London and North Eastern Rai ...
, to gain an unbiased review of their riding qualities. Locomotives No. A803 (K) and No. A890 (K1), and King Arthur class No. E782, were tested on the well-maintained LNER line between and in October 1927, where few problems were found with locomotive stability. On runs between Kings Cross and with the LNER's
dynamometer car A dynamometer car is a railroad maintenance of way car used for measuring various aspects of a locomotive's performance. Measurements include tractive effort (pulling force), power, top speed, etc. History The first dynamometer car was probably ...
, No. A890 was recorded at a top speed of and A803 at , with no problems in riding.Holcroft (1965), p. 145 When these engines returned from the LNER, the Southern Railway's General Manager, Sir Herbert Walker ordered further trials to be led by Sir John Aspinall on the Western section main line near . These were terminated by the Southern Railway's Operating Department, as the riding of the locomotives at speeds near rendered the locomotives unsafe. The instability of No. A890 at speed was attributed to the helical springs on the Bissel truck and bogie.Pringle (1928), p. 28 The 1928 accident inquiry did not attach blame to the Southern Railway for track maintenance or locomotive performance issues, and noted that the prototype had run for eight years over the same stretch of line without complaint.Pringle (1928), p. 17 However, it identified the Brighton batch and No. A890 as being more susceptible to rolling on sharp curves with weak rail joints, although the entire class operated without incident on the former LBSCR network.Pringle (1928), p. 19 The management of the Southern Railway realised that to have any success in operating the K class tanks on other parts of the network, vast stretches of track would require upgrading. With the prospect of storing 20 locomotives whilst the necessary upgrading took place, the management recommended the class be fully withdrawn from service. To recoup the expense of constructing the engines, Maunsell was given permission to rebuild them to the new SR U class 2-6-0 tender engine design in 1928. This decision also reduced the adverse publicity generated by the accident. However, many of the components discarded during the rebuilding process would later be re-used on another 2-6-4 tank locomotive designed to haul heavy freight on short trips: the 3-cylinder W class of 1932.Rowledge (1976), p. 43


Rebuilding

The rebuilding of the class as tender locomotives was cheaper than relaying track, particularly as in most respects the class had performed well. Rebuilding took place at Ashford,
Brighton Brighton () is a seaside resort and one of the two main areas of the City of Brighton and Hove in the county of East Sussex, England. It is located south of London. Archaeological evidence of settlement in the area dates back to the Bronze A ...
and
Eastleigh railway works Eastleigh Works is a locomotive, carriage and wagon building and repair facility in the town of Eastleigh, in the county of Hampshire in England. History LSWR The London and South Western Railway (LSWR) opened a carriage and wagon works at Eas ...
between March and December 1928, where the water tanks, rear bogie and coal bunker were removed.Scott-Morgan (2002), p. 46 The straight-sided variant of Maunsell tender was attached, allowing a greater operational range for the locomotives. The rear bogies were later used on the SR W class 2-6-4 tank locomotives (the only subsequent use of this wheel arrangement by the Southern Railway, and their use was restricted to freight operations around London). The solitary K1 class locomotive was rebuilt in June 1928, and so became the three-cylinder prototype of the SR U1 class.Rowledge (1976), p. 39 The Holcroft valve gear was later replaced with a third set of
Walschaerts valve gear The Walschaerts valve gear is a type of valve gear used to regulate the flow of steam to the pistons in steam locomotives, invented by Belgium, Belgian railway mechanical engineering, engineer Egide Walschaerts in 1844. The gear is sometimes name ...
in February 1932, thus reducing maintenance.Clarke (March 2008), p. 56 None of the rebuilds retained their names.


Performance of the rebuilt locomotives and withdrawal

As members of the U and U1 classes, rebuilds were used mainly on mixed-traffic as well as secondary passenger duties on lines between the main routes. They were used all over the Southern Railway network, but were little-used over the steep track gradients west of Exeter.Herring, Section "U Class", pp. 120–121 The smaller-wheeled N class was preferred amongst crews for the same duties, as high-speed running was rare away from the main lines in the
West Country The West Country (occasionally Westcountry) is a loosely defined area of South West England, usually taken to include all, some, or parts of the counties of Cornwall, Devon, Dorset, Somerset, Bristol, and, less commonly, Wiltshire, Gloucesters ...
. Heavier passenger work was allocated to Bulleid's Unrebuilt ''Light Pacifics'', which were within weight restrictions in this area. The 21 rebuilt locomotives entered British Railways service in 1948. From 1955 a few were given replacement frames at overhaul: these had a shallower curve between the front buffer beam and the smokebox.Haresnape (1983), p. 92 Withdrawals took place between 1962 and 1966, by which time many of the rebuilds were based at
Guildford Guildford () is a town in west Surrey, around southwest of central London. As of the 2011 census, the town has a population of about 77,000 and is the seat of the wider Borough of Guildford, which had around inhabitants in . The name "Guildf ...
shed A shed is typically a simple, single-story roofed structure that is used for hobbies, or as a workshop in a back garden or on an allotment. Sheds vary considerably in their size and complexity of construction, from simple open-sided ones de ...
. Work was taken over by
Oliver Bulleid Oliver Vaughan Snell Bulleid Commander of the Order of the British Empire, CBE (19 September 1882 – 25 April 1970) was a British railway and mechanical engineer best known as the Chief Mechanical Engineer (CME) of the Southern Railway ( ...
's ''Light Pacifics'', and the electrification of much of the former Southern Railway network was imminent, making all the 2-6-0s surplus to requirements from 1963. The final rebuild was withdrawn from service in June 1966.Ian Allan ABC (1966), section: "U class"


Livery and numbering


SECR and Southern Railway

The K class prototype was painted in an unlined dark grey livery with white lettering and numbering. This Maunsell grey livery was introduced by the SECR as a wartime economy measure. On Grouping in 1923, the SR replaced the liveries of the constituent companies with a standard
sage green Sage or SAGE may refer to: Plants * ''Salvia officinalis'', common sage, a small evergreen subshrub used as a culinary herb ** Lamiaceae, a family of flowering plants commonly known as the mint or deadnettle or sage family ** ''Salvia'', a large ...
livery (the colour being that previously used by Urie on the
LSWR The London and South Western Railway (LSWR, sometimes written L&SWR) was a railway company in England from 1838 to 1922. Originating as the London and Southampton Railway, its network extended to Dorchester and Weymouth, to Salisbury, Exeter ...
) with black and white lining, primrose yellow numbering and "Southern" on the tender.Swift (2006), p. 50 From 1925, the K and K1 classes were repainted in a darker
olive green Olive is a dark yellowish-green color, like that of unripe or green olives. As a color word in the English language, it appears in late Middle English. Shaded toward gray, it becomes olive drab. Variations Olivine Olivine is the typical ...
livery, introduced by Maunsell, with plain white lining and primrose yellow markings. When rebuilt into the U and U1 classes, the locomotives were repainted in the olive green livery with "Southern" added to the tender tank.Haresnape (1983), p. 88 This was carried into the Second World War when labour shortages meant that many U class locomotives were painted in plain black, with the result that by 1945 all the class were running in black. The class prototype was initially numbered 790, with the rest following consecutively with a prefix "A" to denote a locomotive designed for the former SECR. The system of prefixes had been adopted by the SR to distinguish between locomotives with identical numbers acquired from different companies, and the K1 class became No. A890 when built in 1925. This system was replaced from 1928 by a renumbering of all locomotives into one sequence, in which the K class rebuilds became Nos. 1790–1809, and the K1 class rebuild became No. 1890.Haresnape (1983), p. 93


Rebuilds in British Railways service

The K and K1 classes were absorbed by
British Railways British Railways (BR), which from 1965 traded as British Rail, was a state-owned company that operated most of the overground rail transport in Great Britain from 1948 to 1997. It was formed from the nationalisation of the Big Four British rai ...
as part of the U and U1 classes in 1948, which were given the BR
power classification A number of different numbering and classification schemes were used for the locomotives owned by the London, Midland and Scottish Railway (LMS) and its constituent companies; this page explains the principal systems that were used. The followi ...
4MT (mixed-traffic) in 1950. This was later revised to 4P3F in the light of operational experience on freight trains.Longworth: Section "U class" The locomotives at first retained their Southern Railway livery, with "British Railways" added to the tender when repaints were due. From 1949 to 1955, the U and U1 class locomotives were gradually repainted in the British Railways mixed-traffic lined black livery with red, cream and grey lining and the British Railways crest on the tender.Bradley (1961), p. 63 Numbers were changed to the British Railways standard numbering system: the series 31790–31809 was allocated to the K class rebuilds, and 31890 to the K1 class.Ian Allan ABC (1958), section: "U class"


Operational assessment and preservation

Sir Nigel Gresley's independent report on the K and K1 classes during the mainline stability trials stated that they were well designed, mechanically reliable and capable of hauling expresses at high speeds on well-maintained track, which meant that they could have been useful additions to the Southern Railway's suburban commuter fleet.Pringle (1928), p. 26 However, they were undoubtedly prone to rough riding and instability, and not only on the poorest quality tracks. The restricted water capacity also limited their use outside the Southern Railway's Central section. The impending electrification of the
Brighton Main Line The Brighton Main Line (also known as the South Central Main Line) is a major railway line in the United Kingdom that links Brighton, on the south coast of England, with central London. In London the line has two branches, out of and station ...
, scheduled for 1932 also meant that fewer duties suitable for heavy passenger tank locomotives would be available in the 1930s. The lack of a suitable role for both classes was considered when the decision was made to rebuild them as U/ U1 tender engines following the Sevenoaks disaster. In rebuilt form they continued to operate until the 1960s, and were capable of attaining speeds in excess of 70 mph (110 km/h) with a greater degree of stability. One K class rebuild has survived: No. A806 ''River Torridge'' – converted to U class No. 1806 – was rescued from
Woodham Brothers Woodham Brothers Ltd is a trading business, based mainly around activities and premises located within Barry Docks, in Barry, Wales, Barry, South Wales. It is noted globally for its 1960s activity as a scrapyard (hence its colloquial name of Bar ...
scrap yard in
Barry, Vale of Glamorgan Barry ( cy, Y Barri; ) is a town in the Vale of Glamorgan, Wales, on the north coast of the Bristol Channel approximately south-southwest of Cardiff. Barry is a seaside resort, with attractions including several beaches and the resurrected Bar ...
,
South Wales South Wales ( cy, De Cymru) is a loosely defined region of Wales bordered by England to the east and mid Wales to the north. Generally considered to include the historic counties of Glamorgan and Monmouthshire, south Wales extends westwards ...
in October 1976 for use on the
Watercress Line The Watercress Line is the marketing name of the Mid-Hants Railway, a heritage railway in Hampshire, England, running from New Alresford to Alton where it connects to the National Rail network. The line gained its popular name in the days w ...
.Great Western Society (2000
Saved from Barry – SR locomotives.
Retrieved 21 June 2009
It was restored to ex-British Railways condition as No. 31806.Langston (2008), p. 112 In August 2014, the locomotive entered service with the Swanage Railway.


See also

* List of SECR K and SR K1 class locomotives


References


Notes


Bibliography

* * * * *Casserley, H.C.: 'End of the Maunsell moguls—the Southern maids-of-all-work' (''Railway World'': 1966, 27), pp. 436–440) *Clarke, Jeremy: 'The locomotives of R.E.L. Maunsell, Part 3: The 'Mogul' family – SECR' (''Steam World'', 2008 (248)), pp. 38–41 *Clarke, Jeremy: 'The locomotives of R.E.L. Maunsell, Part 4: The 'Mogul' family – SR' (''Steam World'', 2008 (249)), pp. 54–57 * * * * * * * * * *Middlemass, Tom: 'The "Woolworths" — Woolwich Arsenal's tentative entry into main line locomotive building' (''Backtrack'', 1990 (4)), pp. 148–54 * *Reynolds, W.J.: 'The Maunsell moguls' (''S.R. Railway Magazine'', 1943, 89), pp. 155–156 * * * *


Further reading

*Fryer, Charles: ''Railway Monographs No.1: The Rolling Rivers'' (Sheffield: Platform 5 Publishing, 1993) *Grayer, Jeffery: "Scuppering the "U-Boats"" in Robertson, Kevin: ''The Southern Way Issue No.7'' (Corhampton: Noodle Books (July 2009)), pp. 60–65. . *Nock, O.S.: ''Great Locomotives of the Southern Railway'' (Guild Publishing/Book Club Associates, 1987) pp. 98–102,115,132–137,154–160. CN 5587 *Robertson, Kevin, ed.: "Scuppering the "U-Boats" – Years Earlier" (''The Southern Way Issue No. 7'': Corhampton, Noodle Books (July 2009)), pp. 66–67. .


External links


The Railways Archive: Accident at Sevenoaks on 24 August 1927


{{featured article K and K1 K and K1 classes 2-6-4T locomotives Armstrong Whitworth locomotives Standard gauge steam locomotives of Great Britain Passenger locomotives