Under the Railways Act 1921 the majority of the railway companies in Great Britain (along with a few in

Northern Ireland Northern Ireland ( ga, Tuaisceart Éireann ; sco, label= Ulster-Scots, Norlin Airlann) is a part of the United Kingdom, situated in the north-east of the island of Ireland, that is variously described as a country, province or region. Nort ...

) were grouped into four main companies, often termed the Big Four. The grouping took effect from 1 January 1923.

The Big Four

The Big Four and their constituent companies, showing route mileage, were: * Great Western Railway (GWR) ** Great Western Railway ** Alexandra (Newport and South Wales) Docks and Railway (ADR) ** Barry Railway (Barry) ** Cambrian Railways (Cambrian) ** Cardiff Railway (Cardiff) **

Rhymney Railway The Rhymney Railway was a railway company in South Wales, founded to transport minerals and materials to and from collieries and ironworks in the Rhymney Valley of South Wales, and to docks in Cardiff. It opened a main line in 1858, and a limite ...

(RhyR) **

Taff Vale Railway The Taff Vale Railway (TVR) was a standard gauge railway in South Wales, built by the Taff Vale Railway Company to serve the iron and coal industries around Merthyr Tydfil and to connect them with docks in Cardiff. It was opened in st ...

(TVR) *** for the list of subsidiary companies and joint railways see

List of constituents of the Great Western Railway The Great Western Railway (GWR) was incorporated by Act of Parliament in 1835 and nationalised on 1 January 1948. During this time it amalgamated with, or purchased outright, many other railway companies. These are listed here in two groups. The ...

* London and North Eastern Railway (LNER) **

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 ...

(GCR) ** Great Eastern Railway (GER) ** Great Northern Railway (GNR) **

Hull and Barnsley Railway Hull may refer to: Structures * Chassis, of an armored fighting vehicle * Fuselage, of an aircraft * Hull (botany), the outer covering of seeds * Hull (watercraft), the body or frame of a ship * Submarine hull Mathematics * Affine hull, in af ...

(H&BR) ** North Eastern Railway (NER) **

Great North of Scotland Railway The Great North of Scotland Railway (GNSR) was one of the two smallest of the five major Scottish railway companies prior to the 1923 Grouping, operating in the north-east of the country. Formed in 1845, it carried its first passengers the fro ...

(GNSR) ** North British Railway (NBR) *** for the list of subsidiary companies and joint railways see

List of constituents of the London and North Eastern Railway The London and North Eastern Railway (LNER) was formed out of a number of constituent railway companies at the grouping in 1923. Main companies The main companies, showing their route mileage, were: * Great Eastern Railway (GER) miles (1,906&nb ...

* London, Midland and Scottish Railway (LMS) ** London and North Western Railway (LNWR); *** including

Lancashire and Yorkshire Railway The Lancashire and Yorkshire Railway (L&YR) was a major British railway company before the 1923 Grouping. It was incorporated in 1847 from an amalgamation of several existing railways. It was the third-largest railway system based in northern ...

(L&YR) amalgamated from 1 January 1922 **

Furness Railway The Furness Railway (Furness) was a railway company operating in the Furness area of Lancashire in North West England. History Formation In the early 1840s, the owners of iron ore mines in the Furness district of Lancashire became interested i ...

(Furness); **

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 ama ...

(MR) **

North Staffordshire Railway The North Staffordshire Railway (NSR) was a British railway company formed in 1845 to promote a number of lines in the Staffordshire Potteries and surrounding areas in Staffordshire, Cheshire, Derbyshire and Shropshire. The company was based ...

(NSR) **

Caledonian Railway The Caledonian Railway (CR) was a major Scottish railway company. It was formed in the early 19th century with the objective of forming a link between English railways and Glasgow. It progressively extended its network and reached Edinburgh an ...

(CR) ** Glasgow and South Western Railway (GSWR) **

Highland Railway The Highland Railway (HR) was one of the smaller British railways before the Railways Act 1921, operating north of Perth railway station in Scotland and serving the farthest north of Britain. Based in Inverness, the company was formed by merger ...

(HR) *** for the list of subsidiary companies and joint railways see List of constituents of the London, Midland and Scottish Railway **The Railways Act 1921 did not extend to Ireland, but Irish lines owned by constituent companies became part of the LMS: ***

Dundalk, Newry and Greenore Railway The Dundalk, Newry and Greenore Railway (DNGR, DN&GR) was an Irish gauge () railway in Ireland. It was conceived in the 1860s to provide a link between the towns in its title and the London and North Western Railway port at Greenore, from ...

(DNGR) (owned by the LNWR) *** Northern Counties Committee lines (NCC) (owned by the Midland Railway) **** The NCC and Great Northern Railway (Ireland) (GNR(I)) operated the County Donegal Railways Joint Committee lines jointly, and these became joint lines of the LMS and GNR(I) after grouping. * Southern Railway (SR) **

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) **

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) ** South Eastern and Chatham Railways' Managing Committee: a working union of the South Eastern Railway and the

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 no ...

*** for the list of subsidiary companies and joint railways see

List of constituent companies of the Southern Railway The Southern Railway in the United Kingdom was one of the "Big Four" railway companies set up after the 1923 Grouping. This list sets out the constituents of the Company. Constituent companies * The London and South Western Railway (LSWR) rout ...

Companies not covered by the grouping

Over fifty railway companies were not covered by the grouping. Those in the following list were those organised on an independent basis, usually providing locomotives and rolling stock also. They are included under classification headings.

Joint railways

Joint lines in this respect were wholly owned by two or more other companies. If not all of the owning companies went into the same group then the joint company could not be grouped. Joint lines did not always operate any services: they owned the track, stations etc. and the services were operated by one or more of the parent companies: *These are those in which the group companies only are concerned: **

Cheshire Lines Committee The Cheshire Lines Committee (CLC) was formed in the 1860s and became the second-largest joint railway in Great Britain. The committee, which was often styled the Cheshire Lines Railway, operated of track in the then counties of Lancashire a ...

: ( GNR, Midland and GCR); now operated under direction of a board of directors appointed by LNER (two-thirds) and LMS (one-third). Length . Rolling stock owned by CLC; locomotive power by LNER. **

Great Western and Great Central Joint Railway The Great Western and Great Central Joint Railway was a railway built and operated jointly by the Great Western Railway (GWR) and Great Central Railway (GCR) between Northolt (in north west London) and Ashendon Junction (west of Aylesbury). It was ...

: GWR and GCR; subsequent to the grouping the parent companies were the GWR and the

LNER LNER may refer to: * London and North Eastern Railway, a railway company in the United Kingdom from 1923 until 1947 * London North Eastern Railway, a train operating company in the United Kingdom since 2018 * Liquid neutral earthing resistor, a typ ...

, but the title was not altered. **

Manchester, South Junction and Altrincham Railway The Manchester South Junction and Altrincham Railway (MSJ&AR) was a suburban railway which operated an route between Altrincham in Cheshire and Manchester London Road railway station (now Piccadilly) in Manchester. The MSJ&AR line operat ...

LNWR The London and North Western Railway (LNWR, L&NWR) was a British railway company between 1846 and 1922. In the late 19th century, the L&NWR was the largest joint stock company in the United Kingdom. In 1923, it became a constituent of the L ...

and GCR; subsequent to the grouping the parent companies were the LMS and the

. **

Midland and Great Northern Joint Railway The Midland and Great Northern Joint Railway (M&GNJR) was a railway network in England, in the area connecting southern Lincolnshire, the Isle of Ely and north Norfolk. It developed from several local independent concerns and was incorporated ...

: ( Midland and GNR; subsequent to the grouping the parent companies were the LMS and the

). Length . This was the largest joint system in the UK, and many of the services were operated by the joint company itself. In addition, it received substantial traffic from the GNR and MR/LMS, but rather less post-grouping from the LNER (which also owned the competing ex- GER system in East Anglia). **

Somerset and Dorset Joint Railway The Somerset and Dorset Joint Railway, also known as the S&D, SDJR or S&DJR, was an English railway line connecting Bath (in north-east Somerset) and Bournemouth (now in south-east Dorset but then in Hampshire), with a branch from Evercreech ...

: ( Midland and

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 ...

). Length . *Joint lines where one or more partners were ungrouped: ** Aylesbury Station: joint between the GW & GC Joint and the Metropolitan and Great Central Joint Committee ** East London Railway: prior to grouping, this railway was owned one-sixth each by the Great Eastern Railway,

, Metropolitan Railway, District Railway; and one-third by the South Eastern and Chatham Railway (as successors to the

and South Eastern Railway, who had owned one-sixth each). After grouping, it was owned half by the Southern, and one-sixth each by the

, Metropolitan and District. Length . Managed and operated by Met; goods traffic by LNER. ** Metropolitan and Great Central Joint Committee: prior to grouping, owned by the Metropolitan Railway and GCR; post-Grouping, Metropolitan and LNER.

Railways not included in group companies

Electric or electric and steam lines

* Railways associated with the

Underground Electric Railways Company of London The Underground Electric Railways Company of London Limited (UERL), known operationally as the Underground for much of its existence, was established in 1902. It was the holding company for the three deep-level "tube"A "tube" railway is an und ...

(the precursor of the

London Passenger Transport Board The London Passenger Transport Board was the organisation responsible for local public transport in London and its environs from 1933 to 1948. In common with all London transport authorities from 1933 to 2000, the public name and brand was Lond ...

(LPTB)): **

Central London Railway The Central London Railway (CLR), also known as the Twopenny Tube, was a deep-level, underground "tube" railwayA "tube" railway is an underground railway constructed in a cylindrical tunnel by the use of a tunnelling shield, usually deep below g ...

: . Trains worked through to Ealing over the Ealing and Shepherd's Bush Railway (GWR) **

City and South London Railway The City and South London Railway (C&SLR) was the first successful deep-level underground "tube" railway in the world, and the first major railway to use electric traction. The railway was originally intended for cable-hauled trains, but owing ...

: **

London Electric Railway The London Electric Railway (LER) was an underground railway company operating three lines on the London Underground. It was formed in 1910 and existed until 1933, when it was merged into the London Passenger Transport Board. History The LER wa ...

: : amalgamation of the

Baker Street and Waterloo Railway The Baker Street and Waterloo Railway (BS&WR), also known as the Bakerloo tube, was a railway company established in 1893 that built a deep-level underground "tube" railway in London. The company struggled to fund the work, and construction di ...

Great Northern, Piccadilly and Brompton Railway The Great Northern, Piccadilly and Brompton Railway (GNP&BR), also known as the Piccadilly tube, was a railway company established in 1902 that constructed a deep-level underground "tube" railway in London.A "tube" railway is an underground rail ...

and Charing Cross, Euston and Hampstead Railway ** District Railway: * Other electric/steam railways: **

Liverpool Overhead Railway The Liverpool Overhead Railway (known locally as the Dockers' Umbrella or Ovee) was an overhead railway in Liverpool which operated along the Liverpool Docks and opened in 1893 with lightweight electric multiple units. The railway had a number ...

: **

Mersey Railway The Mersey Railway was the first part of the passenger railway connecting the communities of Liverpool, Birkenhead, and now the rest of the Wirral Peninsula in England, which lie on opposite banks of the River Mersey, via the Mersey Railway Tun ...

: ** Metropolitan Railway: steam and electric including the

Great Northern and City Railway The Northern City Line is a commuter railway line in England, which runs from Moorgate station to Finsbury Park in London with services running beyond. It is part of the Great Northern Route services, and operates as the south-eastern branc ...

Light and similar railways (standard gauge)

Bideford, Westward Ho! and Appledore Railway The Bideford, Westward Ho! and Appledore Railway (B, WH & A, R) was a railway running in northwest Devon, England. It is unusual in that although it was built as a standard gauge line, it was not joined to the rest of the British railway netwo ...

: closed at time of grouping *

Bishops Castle Railway The Bishop's Castle Railway was a railway company that constructed a railway line in Shropshire, from near Craven Arms to Bishop's Castle. It opened in 1866 but was continuously short of money, and was unable to complete its originally-planned ...

: *

Corringham Light Railway The Corringham Light Railway (CLR) in Corringham, Essex, England was incorporated on 10 July 1899 and opened to freight on 1 January 1901, to passengers on 22 June 1901. It closed to passengers on 1 March 1952 and was absorbed into the Mobil Oil ...

: *

Derwent Valley Light Railway The Derwent Valley Light Railway (DVLR) (also known as The Blackberry Line) was a privately owned standard-gauge railway in North Yorkshire, England, and was unusual in that it was never nationalised, remaining as a private operation all its ...

: *

Easingwold Railway The Easingwold Railway was a long branch line from Alne Station to Easingwold in the Vale of York, England England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its nor ...

: *

East Kent Railway The East Kent Railway (EKR) was an early railway operating between Strood and Faversham in Kent, England, during 1858 and 1859. In the latter year it changed its name to the London, Chatham and Dover Railway to reflect its ambitions to build a ...

: * Glasgow (Cable) Subway: *

Hellingly Hospital Railway The Hellingly Hospital Railway was a light railway owned and operated by East Sussex County Council, used for transporting coal and passengers to Hellingly Hospital, a psychiatric hospital near Hailsham, from the London, Brighton and South Coast ...

: *

Hundred of Manhood and Selsey Tramways The West Sussex Railway was a standard gauge Light rail, light railway between Chichester to Selsey, in West Sussex. The line, which opened in 1897, was also known as Hundred of Manhood and Selsey Tramway. It was opened as a rail tramway in order ...

: * * Kent & East Sussex Railway: * *

Mumbles Railway The Swansea and Mumbles Railway was the venue for the world's first passenger horsecar railway service, located in Swansea, Wales, United Kingdom. Originally built under an Act of Parliament of 1804 to move limestone from the quarries of Mum ...

: *

Nidd Valley Light Railway Nidd Valley Light Railway was a light railway in upper Nidderdale in the West Riding of Yorkshire, England. It was owned by Bradford Corporation Waterworks Department and the corporation also operated its public passenger services. Power & Tract ...

: public; private * North Sunderland Railway: *

Rowrah and Kelton Fell Railway The Rowrah and Kelton Fell Railway was a standard gauge mineral railway in Cumberland, England, which was operated by William Baird and Company of Glasgow, Scotland. It opened in 1877 and closed in 1926. Route The line ran south from Rowrah to ...

: *

Shropshire and Montgomeryshire Railway The Shropshire and Montgomeryshire Light Railway was a railway running from Shrewsbury, England to Llanymynech, Wales, with a branch to Criggion. It was promoted by Holman Fred Stephens, better known as Colonel Stephens, proprietor of several ...

* * Stocksbridge Railway: * Swansea Improvements and Tramways Company: * Wantage Tramway: *

Weston, Clevedon and Portishead Railway The Weston, Clevedon and Portishead Light Railway (WC&PR) was a standard gauge light railway in Somerset, England. It was conceived as a tramway in the 1880s, opening between the coastal towns of Weston-super-Mare and Clevedon in 1897 and compl ...

Light and similar railways (narrow gauge)

Ashover Light Railway The Ashover Light Railway was a narrow gauge railway in Derbyshire, England that connected Clay Cross and Ashover. It was built by the Clay Cross Company to transport minerals such as limestone, fluorite, barytes and gritstone to its wor ...

: ; * Brighton Electric Railway: ; * Camborne and Redruth Tramway: ; * Campbeltown and Machrihanish Railway: ; *

Corris Railway The Corris Railway ( cy, Rheilffordd Corris) is a narrow gauge preserved railway based in Corris on the border between Merionethshire (now Gwynedd) and Montgomeryshire (now Powys) in Mid-Wales. The line opened in 1859 as a horse tramway, runni ...

: ; *

Ravenglass and Eskdale Railway The Ravenglass and Eskdale Railway is a minimum gauge heritage railway in Cumbria, England. The line runs from Ravenglass to Dalegarth Station near Boot in the valley of Eskdale, in the Lake District. At Ravenglass the line ends at Raven ...

: ; * Ffestiniog Railway: ; * Glyn Valley Railway: ; *

North Wales Narrow Gauge Railways The North Wales Narrow Gauge Railways (NWNGR) was a railway company that planned to build a number of inter-connected narrow-gauge railways across North Wales. The first two of these lines - jointly known as the "Moel Tryfan Undertaking" - were ...

: ; * Portmadoc, Beddgelert and South Snowdon Railway: ; * Rye and Camber Tramway: ; *

Snailbeach District Railways Snailbeach District Railways was a British narrow gauge railway in Shropshire. It was built to carry lead ore from mines in the Stiperstones to Pontesbury where the ore was transshipped to the Great Western Railway's Minsterley branch line. Co ...

: ; * Snowdon Mountain Tramroad: ; ; rack railway * Southwold Railway: ; *

Talyllyn Railway The Talyllyn Railway ( cy, Rheilffordd Talyllyn) is a narrow gauge preserved railway in Wales running for from Tywyn on the Mid-Wales coast to Nant Gwernol near the village of Abergynolwyn. The line was opened in 1865Drummond 2015, page 17 ...

: ; * Wolverton and Stony Stratford Tramway: ; owned by LMSR

Railways outside the jurisdiction of the Railways Act 1921

The Railways Act 1921 only extended to Great Britain. Railways in Ireland and the Crown Dependencies were not affected unless owned by a railway company in Great Britain. The railways included in this section were standard gauge, unless otherwise noted: *

Alderney Railway The Alderney Railway on Alderney is the only railway in the Bailiwick of Guernsey, and the only working railway in the Channel Islands. (There is a standard gauge railway at the Pallot Heritage Steam Museum in Jersey, but this provides no actua ...

Belfast and County Down Railway The Belfast and County Down Railway (BCDR) was an Irish gauge () railway in Ireland (later Northern Ireland) linking Belfast with County Down. It was built in the 19th century and absorbed into the Ulster Transport Authority in 1948. All but th ...

; *

Cork, Bandon and South Coast Railway Cork, Bandon and South Coast Railway (CB&SCR), was an Irish gauge () railway in Ireland. It opened in 1849 as the Cork and Bandon Railway (C&BR), changed its name to Cork Bandon and South Coast Railway in 1888 and became part of the Great Sout ...

; ; *

Dublin and South Eastern Railway The Dublin and South Eastern Railway (DSER), often referred to as the Slow and Easy, was an Irish gauge () railway in Ireland from 1846 to 1925. It carried 4,626,226 passengers in 1911. It was the fourth largest railway operation in Ireland oper ...

; ; * Great Northern Railway (Ireland); ; * Great Southern and Western Railway; ; * Guernsey Railway; *

Isle of Man Railway The Isle of Man Railway (IMR) ( gv, Raad Yiarn Vannin) is a narrow gauge steam-operated railway connecting Douglas with Castletown and Port Erin on the Isle of Man. The line is narrow gauge and long. It is the remainder of what was a mu ...

; ; * Jersey Eastern Railway; * Jersey Railway and Tramways; ; * Londonderry and Lough Swilly Railway; *

Sligo, Leitrim and Northern Counties Railway The Sligo, Leitrim and Northern Counties Railway (SL&NCR) was a railway in counties Cavan, Fermanagh, Leitrim and Sligo in north-west Ireland. It consisted of one main line, with no branch lines and remained privately owned until its closu ...

; *

Manx Electric Railway The Manx Electric Railway ( Manx: ''Raad Yiarn Lectragh Vannin'') is an electric interurban tramway connecting Douglas, Laxey and Ramsey in the Isle of Man. It connects with the Douglas Bay Horse Tramway at its southern terminus at Derby Castle ...

; ; ; and ; *

Midland Great Western Railway The Midland Great Western Railway (MGWR) was the third largest Irish gauge () railway company in Ireland. It was incorporated in 1845 and absorbed into the Great Southern Railways in 1924. At its peak the MGWR had a network of , making it Irelan ...

; ;

Miscellaneous railways

The railways included in this section were standard gauge, unless otherwise noted: * Felixstowe Docks and Railway: * Manchester Ship Canal: *

Mersey Docks and Harbour Board The Mersey Docks and Harbour Company (MDHC), formerly the Mersey Docks and Harbour Board (MDHB), owns and administers the dock facilities of the Port of Liverpool, on the River Mersey, England. These include the operation of the enclosed north ...

: * Milford Haven Dock and Railway: * Pentewan Railway: ; ; temporarily closed 1923 *

Trafford Park Trafford Park is an area of the Metropolitan Borough of Trafford, Greater Manchester, England, opposite Salford Quays on the southern side of the Manchester Ship Canal, southwest of Manchester city centre and north of Stretford. Until the l ...