The London and North Eastern Railway (LNER) was one of the four railway companies that were formed in 1923 due to the amalgamation of 1921. During the First World War the government had taken control of the railways for the purpose of the war effort. After the war ended it was decided that the railway companies could not competitively return to their prior state, and so the decision was made to combine the 120 existing railway companies into four companies, which became known as ‘the big four’. Smaller railway companies were merged together to form LNER, these previous companies consisted of; Great Central Railway, Great Eastern Railway, Great Northern Railway, Great North of Scotland Railway, Hull and Barnsley Railway, North British Railway and the North Eastern Railway. LNER was the second largest company of the ‘Big Four’ in terms of route miles (total route mileage amounted to 6700) and became famous for its prestigious high speed trains, including the Flying Scotsman and the Mallard, which reached speeds of 126mph (breaking the world record for steam). William Whitelaw, who was a public figure in Scotland, was appointed the first chairman of LNER operating mainly from the London headquarters. The management of LNER was decentralised as much as possible and one of Whitelaw’s main responsibilities became scrutinising proposals of expenditure, due to the shortage of investments. It was decided that the head of management should be Sir Lewis Wedgewood and it was under his management that three main headquarters should be created to best oversee the company. These areas were; Southern, North-Eastern, with offices being situated in York, and Scotland, which was then divided into Northern and Southern Scotland. By 1928 organisation in LNER had stabilised with the chairman being based in Marylebone, Chief General Manager being based in Kings Cross and the Southern headquarters being based in Liverpool. Sir Nigel Gresley became the first Chief Mechanical Engineer of the company. Each of the big four had a Chief Mechanical and Electrical Engineering department which was formed in 1923 with the creation of each company and after nationalisation in 1948, one CM&EE department was created. Gresley became very influential in the company, not only due to his designs of the Flying Scotsman and the Mallard, but also his Pacific designs and long-distance locomotives with the ability to overcome difficult operating conditions. Gresley died in office in 1941 and was succeeded by Edward Thompson, who remained CME until 1946. Arthur Peppercorn, a student of Gresley’s, succeeded Thompson but remained CME for just 18 months, as nationalisation cut short his career. After the Second World War all four railway companies were in financial trouble. The growth of road transport and the effects of the war had meant that each company was in need of severe maintenance work (LMS calculated it would have to spend £40 million on maintenance). Investors of the railways were also at a loss, the LNER’s investors had received no dividend since 1941. With the arrival of a new labour government in 1945, the decision to nationalise all public transport was put forward and in 1948 the ‘Big Four’ were replaced with the British Transport Commission, which separated LNER into Eastern and North Eastern Regions, as well as surrendering the Scottish territory.

During the First World War the government had taken control of the railways to co-ordinate the war effort. After the war ended it was decided that the railway companies could not competitively return to their prior state, and so the 120 existing railway companies were combined into four companies, which became known as the ‘Big Four’’. The London Midland and Scottish Railway, also known as the LMS, was founded on 1 January 1923. The London and North Western Railway (LNWR), Midland Railway (MR), Lancashire and Yorkshire Railway (LYR), North Staffordshire Railway (NSR), Highland Railway (HR), Furness Railway (FR), Glasgow and South Western Railway (G&SWR) and Caledonian Railway (CR) were merged. These eight large constituent companies were joined by 27 other smaller subsidiary railways. The LMS covered the Western half of the country, stretching from the London and the Midlands, through Yorkshire, Lancashire, and up to Scotland. In all the LMS had a total of 7,790 miles of track, which made it the largest railway of the Big Four. The London termini of the LMS were St. Pancras and Euston stations and it had works at Crewe, Horwich, Wolverton and Derby amongst other locations. In 1934 the LMS moved into a new headquarters at Euston House on Seymour Street (later renamed Eversholt Street) in London. Charles Napier Lawrence, 1st Baron Lawrence of Kingsgate was the first appointed chairman of LMS, he had previously been the chairman of the LNWR between 1921-1923. He was chairman of the LMS for one year, and was succeeded by Sir Guy Granet. The management structure was headed by a chairman and a deputy chairman, there was a board of directors that had initially had 20 members, made of men who previously worked for the constituent companies. The first General Manager was Arthur Watson from the LYR. There was a Deputy General Manager for Scotland, a post first held by D.A. Matthieson, formerly of the CR. J.H. Follows, from the Midland Railway, was the first Chief General Superintendent and S.H. Hunt, formerly of the LNWR, was the first Chief Goods Manager. The post of Chief Engineer was initially held by E.F.C. Trench, formerly employed by the LNWR. The first Chief Mechanical Engineer was G. Hughes from the LYR and his deputy was Sir Henry Fowler, from the Midland Railway. The management structure was re-organised from January 1926 and an Executive was set up, Sir Josiah Stamp was the first President of the Executive. From January 1927 four Vice-Presidents were appointed to replace the general managers on the Executive committee. The line was divided up for operational management into three geographical divisions, which were called Western, Midland and Northern. Each division was overseen by a General Superintendent who reported to the Chief General Superintendent. The main line of the LMS ran from London Euston to Wick over 729 miles. The LMS ran a number of joint railways with the London & North Eastern Railway and the Southern Railway. It ran the Cheshire Lines Committee, the Midland and Great Northern line between Peterborough, the Norwich and Lowestoft and the Manchester, South Junction and Altrincham suburban line with the London & North Eastern Railway. It also joined forces with the Southern Railway to run the Somerset and Dorset line between Bath, Burnham and Bournemouth. The LMS undertook a limited programme of electrification, mainly focusing on suburban lines in London and Manchester. The LMS owned many hotels, including the Queen’s Hotel in Leeds and the iconic Art Deco Midland Hotel at Morecombe Bay. The LMS also ran passenger steamers from Holyhead, Heysham and Stranraer over the Irish Sea to Northern Ireland and the Republic of Ireland. Following the 1947 Transport Act which nationalised the railways, the concerns of the LMS were taken over by the Railway Executive as part of the British Transport Committee. Within the Railway Executive, British Rail: London Midland Region assumed responsibility for the LMS’s former area of operations.

The New Zealand Railways Department (NZR) also known as New Zealand Government Railways was a government department created in 1880. NZR acquired a number of private railways from 1886, including the Waimea Plains Railway Company and the New Zealand Midland Railway Company in 1898. The acquisition in 1908 of the Wellington and Manawatu Railway Company and its railway line marked the completion of the North Island Main Trunk from Wellington to Auckland after 23 years construction. In 1923 the West Coast line opens with the Otira tunnel containing the nation's first electric railway. In 1945 the South Island main trunk from Christchurch to Picton is completed and by 1953 the rail network reached its peak in terms of network reach at 5,689 kilometres. Between 1959 and 1971 numerous country branch lines close across the country as the steam era ends as NZR re-equipped lines with modern diesel locomotives. The NZR was reorganised in 1982 to become an independent commercial company called the New Zealand Railways Corporation.

In 1937 Robert Stephenson & Co. Ltd purchased the locomotive department of R & W Hawthorn Leslie & Co. Ltd. They became Robert Stephenson and Hawthorns Ltd. The policy was to concentrate the building of main line locomotives at Robert Stephenson’s Darlington works and industrial locomotives at Forth Banks. In 1944 Vulcan Foundry acquired Robert Stephenson and Hawthorns Ltd, ending Hawthorns' 137 year connection with Forth Banks. In 1955 Vulcan Foundry became full members of the English Electric group of companies, which became part of the GEC group of companies in 1968.