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British Rail Class 158
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British Rail Class 158
The British Rail Class 158 Express Sprinter is a diesel multiple unit (DMU) passenger train. It is a member of the Sprinter series of regional trains, produced as a replacement for British Rail's first generation of DMUs; of the other members, the Class 159 is almost identical to the Class 158, having been converted from Class 158 to Class 159 in two batches to operate express services from London Waterloo to the West of England.
The Class 158 was constructed between 1989 and 1992 by British Rail Engineering Limited (BREL) at its Derby Litchurch Lane Works. The majority were built as two-car sets; some three-car sets were also produced. During September 1990, the first Express Sprinters were operated by ScotRail; the type was promptly introduced to secondary routes across the Midlands, Northern England, Wales and the South West. The Class 158 enabled the replacement of large numbers of elderly DMUs but also several locomotive-hauled trains as well; this was partially accomplished via the cascading of existing Sprinter units onto other routes. To capitalise on the Class 158's improved onboard amenities in comparison to other rolling stock in use for regional services, the Alphaline branding was launched during the mid-1990s; it was also used for a time in the post-privatisation era.
As a result of British Rail's privatisation in the mid-1990s, the Class 158s were divided amongst various newly created operators broadly along their existing routes. Due to their relatively young age at that time, most operators elected to retain them for the following decades. Several, such as Northern Rail and Arriva Trains Wales, had their Class 158 fleets modernised and refitted with various new facilities, such modifications often including greater accessibility, onboard passenger information systems, Wi-Fi connectivity, and toilet retention tanks. By the 2020s, many Class 158 operators had started to or had replaced the type with newer rolling stock, such as the Class 170 Turbostar, Class 185 Desiro, and Class 197 Civity multiple units.
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. The initial specification developed for the latter concept was relatively ambitious, calling for a maximum speed of 90 mph (140 km/h), acceleration comparable to contemporary EMUs, the ability to couple/work in multiple with existing EMUs, facilitate through-access for passengers, feature pressure ventilation, the ability to assist a failed unit, and to comprise either a three- or four-car consist. This specification led to the experimental British Rail Class 210 diesel-electric multiple unit. However, it was found that relatively expensive equipment was needed for the performance specified, particularly to provide sufficient speed, acceleration, and through-passenger access; maintainability also suffered due to space limitations. It was recognised that a production model assembled from proven components would possess greater reliability and lower maintenance costs; an availability rate of 85 per cent was forecast.
By 1983, experiences with the Class 210 had influenced BR planners to favour procuring a new generation of DMUs, but to also adopt a new specification that were somewhat less demanding than before. Specifically, it was decided to drop the top speed from 90 to 75 mph (145 to 121 km/h), as testing had revealed the higher rate to deliver no perceivable improvement in journey times due to the typically short spacing of the stations the type was intended to serve. Furthermore, it was determined that a propulsion system delivering 7 hp per tonne would deliver sufficient acceleration. The requests for compatibility with other rolling stock were eliminated, although auto-coupling and auto-connecting functionality was added. In addition to a good ride quality, the specification included a sound level of 90 dB when at full speed, an operational range of 1,000 miles (1,600 km), and an interval between major overhauls of five years or 350,000 miles (560,000 km). While the prior generation of DMUs typically used a pair of engines for each power car, the specification called for only a single engine per car, as well as for sufficient cooling so that, even with one failed engine, a two-car unit could maintain a typical service performance without major deficient. It was also intended that the DMU could be assembled akin to building blocks, comprising between two and four cars that could be outfitted with various passenger amenities such as toilets and luggage spaces.
Initially formalised as a business specification, these requirements were transferred into a relatively broad technical specification that avoided any specifics other than those that were deemed essential for compatibility purposes. Thereafter, it was issued to various rolling stock manufacturers for a competitive tender. Under this process, responding manufacturers submitted bids to construct an initial series of three-car demonstration units. A constrained timetable of only 18 months between the date of order to delivery of these prototypes was also specified; this has been attributed as having compelled manufacturers to lean towards existing industrial practices for their submissions. The bid submitted by British Rail Engineering Limited (BREL) was heavily based on its successful Class 455 EMU, sharing its body and the majority of its running gear, albeit equipped with two different power trains. The railway engineering company Metro-Cammell also bid, offered its own design that employed rivetted aluminium construction; this approach produced a meaningful weight reduction over conventional methods. BR officials opted to proceed with a pair of prototypes from both BREL and Metro-Cammell, resulting in the Class 150 and Class 151 respectively.
Between 1984 and 1985, these prototype units were delivered to BR and commenced their trial service period. 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 50 per cent engine-out performance requirements. It was also determined that both types achieved adequate noise levels for its intended service sector, but were also noted that this area would likely pose an issue if they were ever directed towards the higher end of the market. Early concerns regarding the body bending frequency of the Class 151 did not prove to have major substance to them. Ultimately, the Class 150 prototypes proved to be more reliable and an order for 50 two-car units was accordingly issued to BREL, leading to a production batch of Class 150s.
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British Rail Class 158
The British Rail Class 158 Express Sprinter is a diesel multiple unit (DMU) passenger train. It is a member of the Sprinter series of regional trains, produced as a replacement for British Rail's first generation of DMUs; of the other members, the Class 159 is almost identical to the Class 158, having been converted from Class 158 to Class 159 in two batches to operate express services from London Waterloo to the West of England.
The Class 158 was constructed between 1989 and 1992 by British Rail Engineering Limited (BREL) at its Derby Litchurch Lane Works. The majority were built as two-car sets; some three-car sets were also produced. During September 1990, the first Express Sprinters were operated by ScotRail; the type was promptly introduced to secondary routes across the Midlands, Northern England, Wales and the South West. The Class 158 enabled the replacement of large numbers of elderly DMUs but also several locomotive-hauled trains as well; this was partially accomplished via the cascading of existing Sprinter units onto other routes. To capitalise on the Class 158's improved onboard amenities in comparison to other rolling stock in use for regional services, the Alphaline branding was launched during the mid-1990s; it was also used for a time in the post-privatisation era.
As a result of British Rail's privatisation in the mid-1990s, the Class 158s were divided amongst various newly created operators broadly along their existing routes. Due to their relatively young age at that time, most operators elected to retain them for the following decades. Several, such as Northern Rail and Arriva Trains Wales, had their Class 158 fleets modernised and refitted with various new facilities, such modifications often including greater accessibility, onboard passenger information systems, Wi-Fi connectivity, and toilet retention tanks. By the 2020s, many Class 158 operators had started to or had replaced the type with newer rolling stock, such as the Class 170 Turbostar, Class 185 Desiro, and Class 197 Civity multiple units.
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. The initial specification developed for the latter concept was relatively ambitious, calling for a maximum speed of 90 mph (140 km/h), acceleration comparable to contemporary EMUs, the ability to couple/work in multiple with existing EMUs, facilitate through-access for passengers, feature pressure ventilation, the ability to assist a failed unit, and to comprise either a three- or four-car consist. This specification led to the experimental British Rail Class 210 diesel-electric multiple unit. However, it was found that relatively expensive equipment was needed for the performance specified, particularly to provide sufficient speed, acceleration, and through-passenger access; maintainability also suffered due to space limitations. It was recognised that a production model assembled from proven components would possess greater reliability and lower maintenance costs; an availability rate of 85 per cent was forecast.
By 1983, experiences with the Class 210 had influenced BR planners to favour procuring a new generation of DMUs, but to also adopt a new specification that were somewhat less demanding than before. Specifically, it was decided to drop the top speed from 90 to 75 mph (145 to 121 km/h), as testing had revealed the higher rate to deliver no perceivable improvement in journey times due to the typically short spacing of the stations the type was intended to serve. Furthermore, it was determined that a propulsion system delivering 7 hp per tonne would deliver sufficient acceleration. The requests for compatibility with other rolling stock were eliminated, although auto-coupling and auto-connecting functionality was added. In addition to a good ride quality, the specification included a sound level of 90 dB when at full speed, an operational range of 1,000 miles (1,600 km), and an interval between major overhauls of five years or 350,000 miles (560,000 km). While the prior generation of DMUs typically used a pair of engines for each power car, the specification called for only a single engine per car, as well as for sufficient cooling so that, even with one failed engine, a two-car unit could maintain a typical service performance without major deficient. It was also intended that the DMU could be assembled akin to building blocks, comprising between two and four cars that could be outfitted with various passenger amenities such as toilets and luggage spaces.
Initially formalised as a business specification, these requirements were transferred into a relatively broad technical specification that avoided any specifics other than those that were deemed essential for compatibility purposes. Thereafter, it was issued to various rolling stock manufacturers for a competitive tender. Under this process, responding manufacturers submitted bids to construct an initial series of three-car demonstration units. A constrained timetable of only 18 months between the date of order to delivery of these prototypes was also specified; this has been attributed as having compelled manufacturers to lean towards existing industrial practices for their submissions. The bid submitted by British Rail Engineering Limited (BREL) was heavily based on its successful Class 455 EMU, sharing its body and the majority of its running gear, albeit equipped with two different power trains. The railway engineering company Metro-Cammell also bid, offered its own design that employed rivetted aluminium construction; this approach produced a meaningful weight reduction over conventional methods. BR officials opted to proceed with a pair of prototypes from both BREL and Metro-Cammell, resulting in the Class 150 and Class 151 respectively.
Between 1984 and 1985, these prototype units were delivered to BR and commenced their trial service period. 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 50 per cent engine-out performance requirements. It was also determined that both types achieved adequate noise levels for its intended service sector, but were also noted that this area would likely pose an issue if they were ever directed towards the higher end of the market. Early concerns regarding the body bending frequency of the Class 151 did not prove to have major substance to them. Ultimately, the Class 150 prototypes proved to be more reliable and an order for 50 two-car units was accordingly issued to BREL, leading to a production batch of Class 150s.
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