British Rail Class 158

By the beginning of the 1980s, British Rail (BR) operated a large fleet of first generation DMUs, which had been constructed in prior decades to various designs. While formulating its long-term strategy for this sector of its operations, British Rail planners recognised that there would be considerable costs incurred by undertaking refurbishment programmes necessary for the continued use of these ageing multiple units, particularly due to the necessity of handling and removing hazardous materials such as asbestos. In light of the high costs involved in retention, planners examined the prospects for the development and introduction of a new generation of DMUs to succeed the first generation. In the concept stage, two separate approaches were devised, one involving a so-called railbus that prioritised the minimisation of both initial (procurement) and ongoing (maintenance and operational) costs, while the second was a more substantial DMU that could deliver superior performance than the existing fleet, particularly when it came to long-distance services. Both the Class 150 and 151 units were subject to extensive evaluations with the aim of a larger production order being forthcoming for the more successful of the two types. Testing revealed that the Class 150 had exceptional ride quality, as well as fully satisfying the 50per cent engine-out performance requirements. and Gmeinder GM190 final drive unit. The engines were rated at either or , depending on the model. Maximum speed is . Most units were built with two coaches, but a batch of units contained an additional centre car for the busy Transpennine Route. Each vehicle is fitted with a BSI autocoupler at both ends; however, only the cab ends have automatic electrical connecters. This allowed three-car sets to be formed by inserting an additional driving car into a set with an adaptor for two different gangway sizes. ==Description==

Variants A total of 182 Class 158 units were constructed. The majority were built as two-car sets. Seventeen units were produced as three-car units; eight of these units have since had the centre car transferred to different units of the class, whilst another eight have been upgraded and redesignated as the . The majority of units, as originally built by British Rail Engineering Limited (BREL), were configured with standard-class accommodation only; a number of Scottish-based sets were fitted with a small first-class section in one vehicle. Later on, several other sets were retrofitted with first-class accommodation. Passenger facilities and performance refurbished Class 158 (first refurbishment)|alt= Around the time of its introduction, BR was keen to promote the qualities of the Class 158, on one occasion publicly describing it as having brought "new standards of comfort and quality to rail travel on Regional Railways' key long-distance cross-country routes". As originally built, the interiors were carpeted throughout, large "panoramic" windows lined the sides and a variety of seating arrangements were present, including airline-style and bays of four set around tables. Unlike the previous members of the Sprinter family, such as the , the Class 158 was outfitted with air conditioning units, an on-board payphone, power-operated interior doors, a toilet in each carriage, and provision for a refreshment trolley service. Despite an increased top speed of , the Class 158 reportedly promised a smoother and quieter ride in comparison to its predecessors. As a lightweight unit and the first members of the Sprinter group to use disc brakes, autumn leaf mulch built up on wheel rims and prevented the units from correctly operating signalling track circuits. Although this was later solved by installing scrubbing blocks to clean the wheels, temporary solutions were sought during October 1992, with some units split and formed into hybrid units with coaches, the latter possessing tread brakes which cleaned the wheels as a by-product of their standard operation. The air conditioning systems of the Class 158 also proved to be unreliable in service, In the privatisation era, many operators elected either to re-engineer or entirely replace such equipment. As a result, the systems in use and their effectiveness vary considerably across the fleet. The lightweight aluminium body of the Class 158 leads to a good 'route availability' score, ==Operations==

British Rail ScotRail was the first part of British Rail to introduce the Class 158s to public service in September 1990. These were employed on to services, as well as services to and . The Class 158s then went on to be deployed elsewhere in Britain, primarily in the Midlands, Northern England, Wales and the South West. Post privatisation After the privatisation of British Rail, the Class 158 fleet was divided among several franchises: ScotRail The first privatised incarnation of ScotRail inherited a 46-strong fleet which continued in service. Following the introduction of newly built Turbostar units on primary express services in 1999, the Class 158 fleet was reduced in number by six, with those remaining cascaded away to secondary routes such as the Far North Line. During 2003, plans were mooted for a portion of the fleet to be swapped with Class 156 units operated by Central Trains, as the latter were thought better suited to some of the short-distance routes that were being operated by ScotRail's 158s. However, this scheme failed to materialise and, by the mid-2000s, operations of ScotRail's Class 158s ranged from short hops (such as Glasgow Queen Street to ) to rural lines and long-distance expresses, supplementing other express units. In 2010, these units started to appear at Glasgow Central station to run on the Glasgow Central to Edinburgh via Shotts line, and on to the Glasgow Central to Whifflet line. Some additional units have since been acquired from other operators to provide extra capacity. Refurbishment and reliverying has also taken place since privatisation. The original ScotRail franchise applied its own livery to the Class 158s, followed by a further repaint by First ScotRail after it took control of the franchise. The fleet has now gained a permanent blue-and-white livery based on the Scottish Saltire, after Transport Scotland announced in September 2008 that it was specifying a permanent livery for all Scottish trains, which would not be changed in the event of a change of franchisee. Interiors have also seen attention on more than one occasion. The most recent refurbishment of 25 units involved repainting, new seating, extra luggage space and new customer information systems. Toilet retention tanks were also fitted. Transport for Wales (ATW) 158823 at in 2009. Class 158s are required on Cambrian Line services as they are the only Transport for Wales trains fitted with the ERTMS signalling used on the line. in October 2024 In the early days of privatisation, the Class 158 Express Sprinter units were in regular use by Wales & West on its long-distance Alphaline services from South Wales to North-West England, North Wales, Cornwall and , as well as on some Central Trains services to and along the Cambrian Line. Successor companies Wales & Borders (2001) and Arriva Trains Wales (2003) continued to use this type of unit on similar workings, with a total allocation of 40 units also allowing Cambrian Line services to become entirely Class 158-operated. By the end of 2006, a total of 16 units (158815–158817 and 158842–158854) had returned to the leasing company, as Arriva gained exclusive use of the entire fleet which had previously been shared with other train operators. The remaining 24-strong fleet became permanently based at a purpose-built depot in Machynlleth during 2007. Despite initial problems in retro-fitting the necessary 'glass cockpit'-style driver controls, Arriva's Class 158 Express Sprinter units became the first fleet in the UK to be equipped for regular use with the ETCS Level 2 signalling system. Commercial operation under ETCS started on 28 March 2011. Accordingly, the units operate all Cambrian Line services between mid-Wales and Birmingham, and they supplemented the now-withdrawn Class 175 Coradia units on other long-distance routes. During 2009, Arriva also proposed using the fleet to provide a direct service between and London, although this proposal was later rejected by the Office of Rail Regulation. Between December 2010 and October 2012, there was a comprehensive refurbishment of the ATW Class 158 fleet, during which almost the entirety of the interiors was replaced with 'as new' fittings and fixtures. This work, which was funded by the Welsh Assembly Government at a cost of £7.5m, included both interior and exterior repainting, the installation of replacement seating, wall coverings, carpets, lighting, luggage racks and toilet fittings. A passenger information system was also fitted, while selected seats gained at-seat power sockets for mobile phones and laptops. Prior to the early 2010s refurbishment, the fleet had been subject to only minor attention to its interior since a refit by Wales & West during the late 1990s (little more than the fabric on the older seats changed and CCTV fitted) as well as having been only partially repainted into Arriva colours externally. The door controls and exterior destination displays were two of the few elements to be replaced prior to this refurbishment work. During 2017, wi-fi equipment was fitted fleetwide. In June of the following year, the Class 158s were progressively modified for conformance with the Persons with Reduced Mobility (PRM) requirements so that the fleet could be operated beyond 1 January 2020; this work involved the expansion of space allocated to passengers using wheelchairs, the installation of wider internal doorways, and the toilet areas being rebuilt to be fully accessibility-friendly; toilet retention tanks were also fitted at this time. During late August 2018, the first PRM-compliant Class 158 was introduced by ATW. On 14 October 2018, the Class 158 fleet was transferred to the new operator Transport for Wales. During February 2019, the first unit was seen in Transport for Wales colours. As early as 2018, it was being reported that Transport for Wales were planning to replace its Class 158s with newly built multiple units by 2023. East Midlands Railway The Class 158 units were introduced to the East Midlands by Regional Railways Central to replace the on long-distance express services branded as Alphaline, such as to via . Following privatisation, Central Trains operated these services but quickly procured a large fleet of units for such services and transferred the Class 158 fleet to secondary routes such as to and to . East Midlands Trains (EMT) had a fleet of 25 units inherited from Central Trains, with some units transferred from First Great Western and South West Trains. EMR's Express Sprinter units operate long-distance express services, such as Norwich to Liverpool, and secondary non-express workings such as Nottingham to , Nottingham to Matlock. and to . The hourly Norwich to Liverpool service has been criticised for overcrowding, especially between Liverpool and Nottingham. This resulted from the Department for Transport specifying two-coach units in the EMT franchise starting in November 2007. In the light of persistent and excessive overcrowding, with some passengers being left behind on occasions, the DfT eventually admitted that it had made a mistake. Great Western Railway The Wales & West franchise (later Wessex Trains) originally operated twelve Class 158 units on long-distance services on the Wessex Main Line. These units were extended into three-coach formations with the acquisition of further units. Unlike the purpose-built three-car Class 158s and units, the centre car was a Driving Motor with the cab locked out of use and an adapter to connect the different-sized gangways. In 2006, First Great Western (FGW) inherited the Wessex Trains fleet following the merger of the Great Western and Wessex franchises. During late 2007 and early 2008, the FGW fleet was refurbished. Improvements included: re-upholstery of seats, and repainting or replacement of interior fittings, alterations to interior lighting and total replacement of toilets. Additionally, the windows have been replaced with safer laminated glass and Halon fire extinguishers replaced with foam ones. At the same time, the units' engines were overhauled and the units repainted in FGW's own lilac and blue colours. In October 2020, Arriva TrainCare completed a refurbishment of the Class 158 fleet in line with the C6 exam. This included: full interior and exterior repaint, and rebrand to new GWR corporate colours, installation of new air conditioning system and heaters and overhauling the seating and flooring. In addition, a new passenger information system was installed as well as new toilet systems. Northern Trains During 2006, First TransPennine Express started to replace its Class 158s with newer and units. The Class 158s were subsequently transferred to Northern Rail, Central Trains, South West Trains and First Great Western. South Western Railway Currently South Western Railway operates Class 158s from and to ; and on the Salisbury to via service. All five Class 158s were transferred to Virgin CrossCountry as a result of the privatisation process; these were subsequently used on services between and via . During 2003, the company's Class 158s were displaced by the newly built and high-speed diesel tilting trains. ==Accidents and incidents==

• On 25 March 1994 at , 158833, working a Paignton to Cardiff service, ran into the back of a Class 43 HST standing in the platform with a Penzance to Edinburgh train. Thirty-one people were injured. • On 3 December 2005, unit 158856 was involved in an accident at in which two passengers were killed whilst crossing the line. The Rail Accident Investigation Branch (RAIB) criticised the risk assessment at the crossing as inadequate. • On 1 February 2008, the same unit 158856 collided with debris from an overline footbridge, which had just been accidentally demolished by a tipper lorry, near Barrow-upon-Soar. The lorry driver had forgotten to fully lower the tipper body after delivering materials to a site next to the railway, and drove into the footbridge, knocking its superstructure onto the track. The DMU hit the footbridge debris approximately one minute later. Three people including the driver were taken to hospital. • On 22 January 2010, unit 158701 was derailed at due to faulty points. One person sustained minor injuries. • On 21 July 2013, unit 158774 was parked empty at when it was run into by 156402. Eight passengers were injured. The cause was driver error. • On 1 April 2017, unit 158758 collided with the buffer stops at at a speed of . Fifteen people were injured. The cause was driver error. • On 31 October 2021, a South Western Railway Class 159 unit, 159102, collided with Great Western Railway class 158 coupled units, 158762 and 158763, at Salisbury Tunnel Junction, immediately before Fisherton tunnel. A preliminary RAIB report found the cause was poor adhesion conditions which led to the SWR train over-running a signal set at danger. Unit 158763 was written off in the accident. • On 6 February 2024, unit 158856 was involved in another accident in which it collided with a fallen tree and was derailed between and stations. One of the 31 passengers on board was injured. The RAIB opened an investigation into the accident. • On 21 October 2024, two units 158824 and 158841 were involved in a head-on collision at Talerddig in Powys, in which one passenger died and 15 others were injured. ==Overseas sales==

During 1990–1991, BREL built six three-car State Railway of Thailand ASR class units based on the Class 158 for the State Railway of Thailand. ==Fleet details==

Named units and special liveries Some units have received names: • 158701 The Scottish Claymores (de-named) • 158707 Far North Line 125th Anniversary • 158861 Spirit of the South West (de-named) • 158773 Eastcroft Depot (de-named) • 158784 Barbara Castle (de-named) • 158791 County of Nottinghamshire • 158797 Jame Tomlinson (de-named) • 158844 The Northumbrian • 158910 William Wilberforce (de-named) Liveries ==Notes==