The Underground network opened using steam locomotives, these where used on the network for many years with the network being converted to a fully electric railway in the 1960s. Initially the Metropolitan Railway used steam locomotives that where supplied from the Great Western Railway (GWR), however this situation became untenable and the Metropolitan Railway began to order its own rolling stock. Likewise when the Metropolitan District Railway (MDR) opened it used Metropolitan Railway rolling stock, with the intention being that the Metropolitan Railway would take over the Metropolitan District Railway (MDR) services when the railways construction had been completed. This became intolerable because of the costs of constructing the railway, which left the Metropolitan District Railway (MDR) needing to order supplementary rolling stock to use across the railway.

Great West Railway Metropolitan Class

The Metropolitan railway opened using steam broad-guage steam locomotives with condensing apparatus that where constructed by the Great Western Railway (GWR). The fleet consisted of twenty-two locomotives that where constructed between 1862 and 1864, that where constructed in three workshops with different naming systems. The first two batches where constructed by the Vulcan Factory, with its locomotives named after insects, and the final third batch was constructed at the Great Western Railway (GWR) workshops in Swindon. The equipment for these was later removed and the trains where used on the suburban lines around London.

Metropolitan Railway Class A and B

The Metropolitan Railway opened in 1863 with trains provided by the Great Western Railway (GWR) with their Metropolitan Class locomotives, this arrangement ended in August 1863 when the Great Western Railway (GWR) withdrew its services. Consequently the Metropolitan Railway purchased their own locomotives, which needed to be able to condense because the line was underground between Paddington and Farringdon, Beyer Peacock of Manchester tendered for the construction of eighteen locomotive that would be available in six months at the cost of £2,600 each.

The design of the locomotives where based on the development of a locomotive called Beyers which had been constructed for use on the Spanish Tudela and Bilbao Railway. However, John Fowler a Metropolitan Railway engineer is frequently attributed to the design of the locomotives, however he only specified the driving wheel diameter, axle weight and the ability to navigate sharp curves along the line.

The locomotives where delivered in 1864, coming equip with 406 mm x 508 mm (16in x 20in) cylinders, 1.537m (5ft ½in) diamiter driving wheels and weighed approximately 42 tons. The front wheels where based on a Bissel truck, with a boiler pressure of 120PSI and fitted with a 1.1m³ (40ft³) bunker. The locomotives did not come with a driving cabin just a spectacle plate, to reduce the smoke initially coke was burned, although this was changes to smokeless Welsh coal in 1869.

The first eighteen locomotives carried names, initially, with the nameplates being removed during their refurbishment. The locomotives where called:

• Jupiter
• Mars
• Juno
• Mercury
• Apollo
• Medusa
• Orion
• Pluto
• Minerva
• Cerberus
• Latona
• Cyclops
• Daphne
• Dido
• Aurora
• Achilles
• Ixion
• Hercules

These where followed by an additional five units in 1866 and 1868 followed by six in 1869, these where supplied with 1.9m³ (67ft³) boilers with these being changes in 1868 to allow a boiler pressure of 130PSI. Additional rolling stock was needed by 1879, these where a modified design with Adams bogies, and a 2.46m (8ft 1in) wheelbase and shorter than the previous locomotives at 2.69m (8ft 10in); twenty-four locomotives where constructed and delivered between 1879 and 1885.

The numbering of the units was in succession of delivery, with the units built before 1870 being classed as Class A and those constructed after 1879 classified as Class B from 1925. The St Johns Wood Railway received five Burnett locomotives in 1868, these took locomotive numbers 34 - 38 therefore the Class A locomotives consisted of numbers 1 - 33 and 39 - 44 whereas the Class B reused the 34 - 38 numberings further to numbers 50 - 66.

The locomotives where initially a bright olive green with black and yellow accenting, brass was used for the domes and locomotive numbers, with the chimneys capped in copper. Midcared, a shade of the colour dark red, became the colour for the locomotives in 1885, with the domes also painted and this was the standard colour that was continued by the London Transport Passenger Board (LTPB) in 1933.

Seventeen locomotives where reboilered at Edgware Road between 1880 and 1885 with the works continuing at Neasden depot from 1886, where the boiler pressure was increased to 150PSI, after 1894 the wheel diameter was also increased to 1.78m (5ft 10in) and cylinders to 440mm (17 ½in). Cabins for the drivers and crew where introduced in 1895 because it became too hot working inside the tunnels.

There where accidents in 1873 and 1884 which where caused by coupling rods breaking, the cross section was increased in 1885, however the problem was not resolved until 1893 when the Allan Motion was replaced by a Gibson and Lilley link Motion, with all the locomotives modified by 1896.

Experimentally locomotive number 62 was converted in 1898 to operate burning oil rather than coal or coke, however this proved expensive because of the quality that would be needed to burn underground although further experiments with burning oil where carried out later in 1921.

The Metropolitan Railway Class A and B operated across the entire Metropolitan Railway, which included the Hammersmith and City line today and the East London Line which is a part of the London Overground network today. In 1884 the locomotives where stabled at:

The electrification of the lines within central London between 1905 and 1906, the locomotives where redundant. The first locomotive to be withdrawn was in 1897 when locomotive number 1 was evolved in an accident at Baker Street and forty had been either sold or scrapped by 1907. Thirteen locomotive where still in use for shunting, departmental work and working trains on the Brill Tramway in 1914 but the remainder had been sent to R Fraser for scrapping. The closure of the Brill Tramway in 1935, the purchase of other locomotives and the changes to London and North Eastern Railway (LNER) freight the fleet except one locomotive, number 22 which was sold to the Metropolitan District Railway (MDR), where scrapped by 1936. Locomotive number 22 survived until 1931 having been sold to the Metropolitan District Railway (MDR) in 1925. Other locomotives also survived, outside the fleet on the Brill Tramway, locomotive number 7 survived on the Mersey Railway until 1939 and locomotive number 44 which survived until 1948 on the Pelaw Main colliery.

There is one locomotive, which has been preserved at the London Transport Museum, the Metropolitan Railway Class A locomotive number 23 also known as London Transport number 45.

Metropolitan Railway Class C

The Metropolitan Railway Class C locomotives was a group comprising of four locomotives that where constructed by Nielson and Company in 1891. These where originally Q Class locomotives for the South Eastern Railway and where fitted with condensing apparatus for operating in a tunnel.

Metropolitan Railway Class D

The Metropolitan Railway Class D locomotives was a group comprising of six locomotives that where constructed by Sharp Stewart and Company between 1894 and 1895. Four of the locomotives ran from Baker Street to Aylesbury with two locomotives running between Verney Junction and Aylesbury, the Baker Street fleet where fitted with condensing apparatus but this was later removed. These where withdrawn in 1920, with some being sold and others scrapped. There are no surviving locomotives.

Metropolitan Railway Class E

The Metropolitan Railway Class E locomotives was a group comprising of seven locomotives that where constructed between 1896 and 1901, four where constructed by Hawthorn Leslie and Company Newcastle, with the remaining three being constructed at their works in Neasden.

After an accident which resulted in the scrappage of locomotive number 1, a locomotive became its replacement, with the remainder being given locomotive numbers 77 to 82. Condensing apparatus was fitted to locomotive number 77, however it is unlikely the whole class received this equipment and this was later removed.

There is one surviving unit of Metropolitan Railway Class E locomotive which is still preserved today. The last passenger service for this train was in 1961 with it being withdrawn from service completely in 1965, the locomotive was preserved and is still preserved by the Buckingham Railway Centre. The plan was to scrap the locomotive, however, a London Transport Mechanical Engineering Apprentice of 19 years old began the Met Tank Appeal in 1962. The objective of the find was to save the last remaining Metropolitan Railway Class E locomotive. London Transport offered £500 for the locomotive and the fund had raised over £1000, despite this an inspection showed the underframe was cracked and the locomotive was unable to be steamed therefore the locomotive was not suitable for preservation.

As a result, the locomotive L44 was offered as a replacement. The London Railway Preservation Society stored the locomotive at Bishops Sortford and Luton, with the locomotive being transferred during the mid 1960s to the Quinton Railway Society who could provide a more secure and permanent base for the locomotive while displaying the locomotive in the newly established museum in Buckinghamshire. The locomotive L44 became known as locomotive 1 and became maintained to mainline condition and occasionally being used with 'Steam on the Met' events between 1989 and 2000.

The locomotive received a full overhaul during 2001.

The first event the locomotive attended after its overhaul was at the Bluebell Railway, arriving on 24 June 2007 for the Bluebell 125 celebrations and was paired with four Metropolitan Railway carriages which have bee preserved by the Bluebell Railway.

The locomotive was also used at events at Barrow Hill during August 2008 and Llangollen during October 2008.

An appeal to allow for the restoration of the unit for the next decade was launched in 2010, this would enable the locomotive to be participate in further heritage events across the country.

The locomotive was also used with the Metropolitan 150 celebrations, which celebrated 150 years since the opening of the first underground railway in London on 10 January 1863. The locomotive was loaned from the Buckinghamshire Railway Centre to the London transport Museum where several trips where arranged along the Metropolitan Railway route between Olympia and Moorgate via Edgware Road during the weekends in January 2013. Further celebrations where conducted and on the 9 January 2013 the locomotive was ran from Paddington (Bishops Road) to Farringdon, the original route of the Metropolitan Railway when it opened. For the celebrations the locomotive was coupled with a Metropolitan Railway Milk Van numbered 4 and the Metropolitan Railway Jubilee Carriage numbered 353, this is the oldest operational tube carriage. The train also included a Metropolitan Electric Sarah Saloon carriage number 12 and a series of Ashbury Carriages which where loaned by the Buckinghamshire Railway Centre, which operated the Chesham shuttle comprising of carriage numbers 387, 412, 394 and 368. There where several preservation bodies that where evolved in the events across the London Underground network to celibate 150 years of the London Underground.

Metropolitan Railway Class F

The Metropolitan Railway Class F locomotives was a group comprising of four locomotives that where constructed by the Yorkshire Engine Company in 1901. They where numbered 90 to 93, being used for freight over the Metropolitan Railway mainline, they where withdrawn in 1957 and scrapped in 1962.

Metropolitan Railway Class G

The Metropolitan Railway Class G locomotives where a group comprising of four locomotives that where constructed by Yorkshire Engine Company in 1915. These where numbered 94 to 97 but also had names and was the last class of Metropolitan railway rolling stock that did.

The G class locomotives had various duties on the Metropolitan Railway before 1937 when they where transferred to the London and North Eastern Railway (LNER), where they were numbered 6154 - 6157 and became the M2 class until 1943 when they where withdrawn, being scrapped in 1948.

Metropolitan Railway Class H

The Metropolitan Railway Class H was a group comprising of four steam locomotives which where constructed in 1920 by Kerr Stuart and Company in Stoke on Trent. These where a notable addition to the Metropolitan Railway fleet, serving the mainline as passenger express trains between Rickmansworth today (Harrow then) and the change over point for Aylesbury or Verney Junction, the locomotives cost £11,575 each.

Designed by the Metropolitan Locomotive and Chief Electrical Engineer, Charles Jones, these had a maximum hauling capacity of 250 long tons and negotiate curves of up to 91m (300ft) radius. These where delivered between October 1920 and June 1921, enabling the retirement of the Metropolitan Railway Class C and Metropolitan Railway Class D locomotives, these where considered to be good engines and removed six minuetes from the running times during their lives being worked as Metropolitan Railway express trains. The Metropolitan Railway numbered the locomotives 103 - 110.

The transfer of steam services from the London Transport Passenger Board (LTPB) to London and North Eastern Railway (LNER) in 1937, the eight locomotives where included to work the same trains, being renumbered 6415 - 6422 by the London and North Eastern Railway (LNER) and reclassifying them as H2 stock. During the 1940s the locomotives where transferred to Nottingham to work over the former Great Central Railway, these where withdrawn between 1942 and 1947 and where all scrapped.

Metropolitan Railway Class K

The Metropolitan Railway Class K was a group comprising of six steam locomotives, that where constructed by Armstrong Whitworth in 1925, with boilers that where made by Robert Stephenson and Company in Darlington. These locomotives where numbered 111 - 116 and where made to the design of the N class locomotives that where operating on the South Eastern and Chatham Railway. The trains where mostly used for heavy freight on the Metropolitan Railway and occasionally used with passenger services. These where transferred to the London and North Eastern Railway (LNER) in 1937, being renumbered 6158 - 6163 and reclassified L2. These where withdrawn between 1943 and 1948 and where all scrapped.

District Railway Steam

When the Metropolitan District Railway (MDR) began its services it had rolling stock that was provided by the Metropolitan Railway. However, in 1871 the Metropolitan District Railway (MDR) needed to own its own rolling stock, which culminated in an order for twenty-four condensing steam locomotives was placed with Beyer Peacock and Company which would be similar to the Metropolitan Railway Class A locomotives. The locomotives came equip with 410mm (16in) by 510mm (20 in) cylinders, 1.537m (5ft ½in) diameter driving wheels and weighed 42 tons when they where in working order. The boiler pressure was maintained at 120PSI, the front wheels being on a Bissel trunk and was fitted with a 1.1m³ (40ft³) bunker. These where intended for use on the railway underground therefore there was no drivers cabin supplied, but a weatherboard with a bent-back top and backplate of the bunker was able to be risen to provide protection when the train was driven with the dunker first. In order to reduce the smoke in the underground sections of the railway, initially the Metropolitan Railway used coke however this was changed in 1869 to Welsh smokeless coal. The only noticeable difference between the District and Metropolitan trains was the chimney style which was different and the inclusion of a bent-back top weatherboard.

The locomotives where later made from an Adams bogie replacing the Bissel truck and the earlier locomotives where modified.

There was a total of fifty-four locomotives that where purchased for the Metropolitan District Railway (MDR) and they remained in service until 1905 when the Metropolitan District Railway (MDR) was electrified, displacing the rolling stock. The fleet had been sold baring six locomotives by 1907, two locomotives, locomotive numbers 33 and 34, where retained for use departmentally by 1925, although in 1926 locomotive number 33 was scrapped and replaced by a Metropolitan Railway Class A locomotive number 22 which became Metropolitan District Railway (MDR) locomotive number 35, with both of the locomotives being replaced by 1931 by two goods vehicles that where purchased from the Hunslet Engine Company. These where passed to the London Transport Passenger Board (LTPB) in 1933 and numbered L30 and L31 however these where subsequently withdrawn in 1963.