Class 185 diesel multiple units

Class 185 diesel multiple units
Name	Class 185 diesel multiple units
Manufacturer	Siemens Transportation Systems
Family	Desiro
Built	2005–2006
Formation	3-car sets
Operator	multiple
Carbody	Steel
Maxspeed	100 mph (161 km/h)
Engine	Cummins QSK19
Poweroutput	1,400 kW
Transmission	Diesel-hydraulic

Class 185 diesel multiple units are a fleet of three-car diesel multiple units built by Siemens under the Desiro family for operation in the United Kingdom. Introduced in the mid-2000s to replace older rolling stock, they were procured by TransPennine Express for intercity services across northern England and into Scotland and Wales. The units combined modern traction, passenger amenities, and crashworthiness features to meet contemporary standards set after notable accidents and regulatory changes. Their deployment influenced franchise rolling stock strategies for operators including FirstGroup, Arriva, and later operators on regional routes.

Design and development

The Class 185 design evolved from the Siemens Desiro UK programme, drawing on experience from Deutsche Bahn and export orders such as those for Norfolk Southern and ÖBB. Procurement was driven by the Strategic Rail Authority and franchise competition involving First TransPennine Express and Northern Rail. Technical and operational requirements referenced crashworthiness lessons from the Cambridge crash investigations and standards promoted by the Office of Rail Regulation. Manufacturing took place at Siemens' facilities with supply-chain input from Cummins for powerplants and Voith for transmissions, reflecting UK rolling stock supply links to Bombardier Transportation and Alstom component networks.

Technical specifications

Each three-car Class 185 set uses a Cummins QSK19 diesel engine per car, coupled via a Voith T312 transmission to deliver approximately 1,400 kW total to the train. The steel bodyshell incorporates crash-optimised structures influenced by standards from Rail Safety and Standards Board and complies with the Railways and Other Guided Transport Systems (Safety) Regulations 2006. On-board systems include Train Protection & Warning System compatibility, Automatic Warning System interfaces and provision for European Train Control System fitting. Passenger features originally included air-conditioning, power sockets, and luggage racks complying with accessibility principles from the Disability Discrimination Act 1995 as applied to railway services.

Operations and deployment

Initially introduced on intercity routes across the North West of England, North East England, West Yorkshire, and services extending to Glasgow Central and Manchester Airport, the Class 185 became a backbone for TransPennine Express long-distance services. Subsequent timetable changes and franchise reorganisations saw sets allocated to regional operators including Northern Trains and subleased to operators for relief services during electrification programmes affecting West Coast Main Line and other corridors. Depot allocations have included locations such as Longsight Depot and Heaton TMD, reflecting maintenance agreements with companies like Siemens Mobility and contractor partnerships with DB Schenker.

Refurbishments and modifications

Over their service life, Class 185 units underwent interior refurbishments to update seating, passenger information systems and accessibility features to comply with amendments from the Rail Vehicle Accessibility Regulations. Modifications have included installation of enhanced CCTV, retrofitting of passenger Wi-Fi infrastructure influenced by industry trends seen with operators like Virgin Trains and Govia Thameslink Railway, and minor traction control software updates provided by Siemens in response to operational feedback during winter conditions similar to those encountered on routes serving Scotland. Some sets received livery changes following franchise transitions, coordinated with corporate identity programmes at FirstGroup and other franchisees.

Incidents and safety record

The Class 185 fleet has been involved in a number of incidents, investigated by the Rail Accident Investigation Branch and reported to the Office of Rail and Road. Investigations have examined wheel-slip behaviour, braking performance in adverse conditions reminiscent of problems highlighted after the Grayrigg derailment, and collisionworthiness in lower-speed impacts. Outcomes included recommendations for maintenance regimes, software adjustments, and operator training updates administered by franchise holders and maintenance contractors such as Network Rail-affiliated teams. Overall, the units have had a safety record comparable to contemporaneous DMUs when assessed against national performance statistics compiled by the Department for Transport.

Fleet details and numbering

Class 185 sets were numbered in the 185001–185xxx series as allocated at introduction, with individual carriages carrying distinct identification consistent with TOPS coding and vehicle acceptance procedures overseen by the British Rail legacy numbering conventions. Transfers between operators required temporary rebranding and were recorded in fleet registers maintained by RSSB and operator asset managers including Angel Trains and Eversholt Rail Group, which have been lessors for UK rolling stock.

Preservation and future status

Preservation interest in operational diesel fleets has involved groups associated with heritage sites like the National Railway Museum and regional preservation societies such as those operating at Keighley and Worth Valley Railway. Given ongoing network electrification schemes promoted by the Department for Transport and fleet replacement programmes by major operators, the long-term future of Class 185 units may involve cascading to secondary operators, leasing regimes managed by major lessors, or selective preservation of units of historical interest by heritage organisations. Decisions will reflect policy toward diesel traction, exemplified by legislative and operational shifts seen in the wake of wider decarbonisation strategies.

Category:Diesel multiple units of the United Kingdom