Steam shed

Laira was the location of the temporary terminus of the South Devon Railway from 5 May 1848 when a small engine shed would have been provided. With the completion of the line to Plymouth Millbay railway station on 2 April 1849 a new shed was provided there and the facilities at Laira dismantled, although it remained a junction for the branch line to Sutton Harbour which was mixed gauge for the use of the Plymouth and Dartmoor Railway.

The Great Western Railway, which had amalgamated with the South Devon Railway on 1 February 1876, a new engine shed opened at Laira in 1901^[2] on a site inside a triangle of lines formed by the main line, Sutton Harbour branch, and a curve that was mainly used by London and South Western Railway trains to reach their terminus at Plymouth Friary.^[3] A sewerage treatment facility and poor ground conditions constrained the site of the shed to the north west corner of the triangle (near Lipson Junction) . It was adjacent to the Embankment Road with the estuary of the River Plym just the other side of the road. The shed was a 185 ft (56 m) brick roundhouse with a 65 ft (20 m) turntable in the middle. 28 lines radiated from the turntable, one for access and the remainder for stabling locomotives. Loocmotives approached from the east (Laira Junction) passing a coaling stage.^[4]

A small railway station known as Laira Halt was opened on the adjacent main line on 1 June 1904 but closed again on 7 July 1930.^[5]

Initially Laira was only used for goods locomotives but after the passenger locomotive shed at Millbay closed in 1924 it became very crowded. In 1931 a new 210 ft (64 m) long and 67 ft (20 m) wide shed with four tracks was brought into use just south of the original roundhouse, funded by a government loan under the Development (Loan Guarantees and Grants) Act 1929. This became known as the 'Long Shed' or 'New Shed'.^[6] At the same time additional sidings were laid near the coaling stage (which was doubled in length) and a second track connected to give a separate exit route from the roundhouse. The new shed was built over part of the area previously used by the sewerage treatment facility. A new line connected Laira Junction with Mount Gould Junction (the southern point of the triangle of lines surrounding the shed. This line became known as the 'Speedway' and allowed locomotives to turn on the triangle rather than on the turntable inside the roundhouse.^[7]

During World War II a covered extension was added on the south side of the coaling stage to give an additional place to refuel locomotives.^[7] In 1947 some steam locomotives were converted to burn oil rather than coal. Oil tanks were installed alongside the siding to the south of the Long Shed.^[8]

Diesel shed

Warship Class diesel-hydraulic locomotives started to appear in 1958 and were at first accommodated in the Long Shed alongside steam locomotives until the diesel maintenance depot had been finished.^[6] The Laira marshalling yard alongside Embankment Road was closed in 1958 to make room for carriage sidings and a new diesel shed, which was fully opened on 13 March 1962, although parts had been in use since 1960.^[9]

Laira was designed for the servicing and heavy maintenance of the diesel-hydraulic locomotives favoured by the Western Region of British Railways, the first of the region's purpose designed large diesel depots. It also handled the local diesel electric shunter and DMU fleets, although servicing of the latter was done initially at Belmont sidings at Millbay.^[9]

The diesel shed was in reinforced concrete and comprised three adjoining buildings. The servicing and maintenance building that covers roads 1–4 is on the western side of the shed; number 1 road is equipped with a wheel lathe and lifting jacks for bogie changes. The central building was the Heavy Maintenance Shed; engines can be removed and repainting undertaken on the two roads, numbers 5 and 6. The final three roads were another servicing shed on the eastern side of the site.^[6] Beside this was a small covered area with fuelling points outside in the yard, supplied by a 45,000 gallon fuel tank.^[9] A small group of buildings behind the shed house stores and a workshop for shed equipment.^[8] Carriage washing takes place south of the shed at Mount Gould.

After the withdrawal of steam from the area in 1964, the roundhouse was closed on 13 June 1965 and the area used for additional siding space.^[10][2][11] This area was later modernised and fenced off in readiness for servicing the Nightstar Channel Tunnel sleeper coaches, but the proposed service from Plymouth to Paris Gare du Nord never materialised.^[8]

On 30 September 1981 a new shed, 240 m (790 ft) long was opened on the site of the smaller servicing shed on the east side of the site. This can accommodate the eight coaches and two Class 43 power cars of a High Speed Train set.^[6] An additional covered track was later added in preparation for the proposed Nightstar services.^[8]

After the replacement of High Speed Trains on London services, one road in the shed was leased to Hitachi to maintain the Class 800 and Class 802 'InterCity Express Trains' (IETs) that replaced them. A number of Class 43s continued to be based at Laira to operate four-coach services to Penzance and Cardiff Central. In Edinburgh, the depot at Craigentinny was no longer able to maintain CrossCountry's Class 43s as the space was needed by Hitachi for IETs so the 12 power cars and 5 sets of coaches were transferred to Laira.^[12] CrossCountry will withdraw its Class 43s by October 2023 when their lease ends.^[13] Great Western Railway has started to reduce the number of its Class 43-powered services in December 2022 with the aim of withdrawing most of them by December 2023. The space freed will allow them to move the maintenance of all their Class 802s to Laira.^[14][15]