British Rail Class 88
The Class 88 is a type of mainline mixed traffic electro-diesel locomotive manufactured by Stadler Rail for Direct Rail Services (DRS) in the United Kingdom. The locomotive is part of the Stadler Euro Dual family. It is the first dual-mode locomotive in the UK to use the 25 kV AC electrification.
|British Rail Class 88|
Amid the fulfillment of DRS' order for the Class 68, Stadler's team proposed the development of a dual-mode locomotive that could be alternatively powered by an onboard diesel engine or via electricity supplied from overhead lines (OHLE). Having been impressed by the concept, DRS opted to place an order for ten Class 88s during September 2013. Having been developed alongside the Class 68, considerable similarities are shared between the two locomotives, amounting to roughly 70 percent of all components being shared.
Testing of the first Class 88 was undertaken at that Velim Test Centre in the Czech Republic during 2016; these trials proved to be relatively smooth. During July 2016, 88 001 made the type's first official public appearance. During January 2017, 88 002 Prometheus was the first Class 88 to be delivered to the UK. All ten Class 88s were delivered by March 2017. During June 2017, the type entered regular service with DRS; examples have been typically used to haul freight trains, although they are also fitted for hauling passenger services as well.
During January 2012, Direct Rail Services (DRS) announced that it had ordered a total of 15 new diesel locomotives from Vossloh España (now Stadler Rail). These locomotives, which entered service in the UK as Class 68, were part of the company's Eurolight family, redesigned to fit the smaller UK loading gauge. DRS had opted to procure a clean-sheet design after examining various existing alternatives, such as the ubiquitous British Rail Class 66 locomotive, which the company's management determined to be incapable of satisfactorily replacing its aging fleet of Class 20s, largely due to inefficient engines and elevated operating costs. Stadler undertook development of the Class 68 over an 18 month period, during which the company studies several derivatives and modifications, including the use of alternative powerplants. Having presented such proposals to DRS, the latter became particularly interested in the electro-diesel arrangement, as the company's management recognised there was a potential role for a dual-mode locomotive in the UK market.
During September 2013, DRS announced that it had placed an order for a further ten locomotives, which were designated as the Class 88. The most distinctive difference between the Class 88 and the preceding Class 68 was that these new units would harness a dual-mode electro-diesel propulsion system. Accordingly, these locomotives could be powered either via overhead lines (OHLE) or by its onboard diesel engine. In comparison to conventional diesel locomotives, this arrangement enables operational costs to be significantly reduced when diagrammed on routes partially or entirely under OHLE, under which the diesel engine can be deactivated. The Class 88 is the first dual-mode locomotives in the UK to use the 25 kV AC electrification, as the only other electro-diesel locomotives to have entered service on the British network were the Class 73 and Class 74, which operated in the Southern Region using third rail electrification.
The Class 88 is part of the Stadler Euro Dual family. This is a range of dual-mode locomotives that are fitted both with a pantograph, to collect electricity from overhead wires, and a Caterpillar diesel engine. The UK version is able to run either on electrified lines using the pantograph, which is the UK's standard OHLE current at 25 kV AC, or away from electrified lines with the Caterpillar C27 950 hp (710 kW) engine. Dual-mode locomotives have previously been mooted for freight use in the UK, using the "Last Mile" principle, where a primarily electric locomotive is fitted with a small diesel engine to allow locomotives to run without a load to non-electrified freight sidings. However, the Class 88 is a fully dual-mode locomotive, with the diesel engine powerful enough to haul a train on its own, although with only 17.5 percent of the power it would otherwise have in electric mode.
In the majority of its aspects, the Class 88 featured a high degree of commonality with the preceding Class 68, including the use of an identical bodyshell, cab, brakes, bogies, traction equipment, control software; roughly 70 percent of all components are shared between the two classes. Akin to the Class 68, the Class 88 can achieve a maximum speed of 100mph, sufficient for regular passenger operations, while operating under OHLE, it has a power output of 4,000 kW (5,360hp). Under diesel power, provided by its 12-cylinder Caterpillar C27, it has a maximum power output of 708kW (950bhp); however, the maximum tractive effort is available in either mode. The locomotive's engine, which is compliant with the current EU Stage IIIB emission restrictions, has limited available power as a result of the customer's choice to give the Class 88 comparable power to a traditional Class 20.
The Class 88 is outfitted with both dynamic and regenerative braking systems for the locomotive, along with air braking apparatus for the whole train. When applying regenerative braking, up to 4MW of power may be returned to the OHLE via the catenary. For electricity generation while operating under diesel power, the engine drives an additional traction motor that functions as an alternator, thus avoiding the need for installing a bespoke alternator. According to rail industry periodical Rail, the Class 88 has acceleration comparable to a modern family car when operating 'light', typically taking 13 seconds to accelerate from stationary to 60mph.
Testing and deliveryEdit
During April 2016, the first example of the Class, 88 001, was dispatched to the Velim Test Centre in the Czech Republic, which it was subject to a series of proving trials. The vehicle approvals process included the hauling of a 1,500-tonne train, along with repetitive tests under differing conditions to judge performance; particular attention was paid to the switching process between diesel and electric modes. The various electrified lines of the UK feature around 35 different variations of catenary; the interface between these diverse types and the Class 88's pantograph was a critical part of the acceptance process. According to rail industry periodical Rail, the data gathered during the type's trials showed promising results. During July 2016, 88 001 made the class's first official public appearance, while 88 003 was exhibited at InnoTrans two months later.
During January 2017, no. 88 002 Prometheus became the first of the class to be delivered to the UK, arriving via the Port of Southampton and being transferred by road to the Carlisle Kingmoor TMD. 88 002 was initially used for homologation purposes to secure approval from the Rail Safety and Standards Board (RSSB) for the type's operation in the UK. All ten Class 88s were delivered by March 2017. During July 2017, it was announced that the Class 88 had entered into revenue service with DRS in the previous month, three examples having been used to haul freight trains within the first four weeks of operations. Initially, use of the onboard diesel engines was avoided while sufficient training was delivered to all drivers on the class and minor modifications were being made by the manufacturer.
DRS has procured the Class 88 to serve as a mixed-traffic locomotive, capable of operating both passenger and freight services. Primarily, the type has been used by DRS to haul freight using electric locomotives without the need to hire in electric traction from other operators. As with the Class 68, they are also capable of operating passenger trains.
Even prior to the type entering service, it was decided that the first duty of DRS' Class 88 fleet would be the contracted services between Daventry and Mossend on behalf of the supermarket chain Tesco. The service's path has been timed for an electric locomotive, and previously necessitated the use of a pair of Class 68s working in multiple. Other diagrams for the Class 88 have been focused on those that have previously been run under the wires with diesel traction. So far, the type is almost entirely confined to Daventry - Mossend intermodal traffic and nuclear flask trains across the north of England and Scotland.
All of the Class 88 locomotives have been named, with seven of the ten locomotives reusing names from the 1950s vintage Class 77s, later sold to the Netherlands as NS Class 1500, while one locomotive (88002) bears the name of a former Class 76 locomotive.
|Class||Operator||No. Built||Year Built||Loco nos.|
|Class 88||Direct Rail Services||10||2015–16||88001–88010|
- "Ready for the '88' revolution". railmagazine.com. 19 December 2016.
- "Direct Rail Services orders 15 Vossloh EuroLight UK locomotives". Railway Gazette International. 5 January 2012.
- "DRS orders ten dual-mode Class 88s." Rail, issue 731. 18 September 2013, p. 7.
- Briginshaw, David (25 September 2014). "Electro-diesel locomotive debuts at InnoTrans". International Railway Journal. Retrieved 12 February 2016.
- Nicholls, Mark, ed. (March 2018). "Stadler's Revolutionary Class 88". Railways Illustrated. Vol. 16 no. 3. Stamford: Key Publishing. p. 38. ISSN 1479-2230.
- "Bombardier launches Traxx electro-diesel". Railway Gazette International. 10 May 2011. Archived from the original on 12 May 2011. Retrieved 12 February 2016.
- Johnson, Marc (1 April 2014), "Sleek Lines", www.therailengineer.com, retrieved 12 February 2016
- "Beacon Rail and DRS order dual-mode locos", www.modern-railways.com, 12 September 2013
- Harris, Nigel, ed. (1 February 2017). "Direct Rail Services' first '88' arrives in UK". Rail Magazine. No. 819. Peterborough: Bauer Media. p. 15. ISSN 0953-4563.
- Hewitt, Sam (19 July 2017). "First Revenue-Earning Freight for DRS Class 88". railwaymagazine.co.uk.
- Devereux, Nigel (15 March 2017). "DRS Class 88s to revive Woodhead electric names". The Railway Magazine. Retrieved 16 June 2020.
- Milner, Chris, ed. (July 2020). "Track Record". Railway Magazine. Vol. 166 no. 1, 432. Horncastle: Mortons Media. p. 53. ISSN 0033-8923.
- Report of launch event (includes photo)
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