Rival companies compete to run Underground trains in Yorkshire
Two companies have come up with broadly similar solutions to the Northern rolling stock problem. The Huddersfield Connectivity conference heard presentations from Vivarail and The York Transport Company to convert electric London Underground District Line ‘D’ stock to diesel traction. The stock is being phased out and should become available later in the year.
Northern Trains has an ageing fleet with an average age of 24 years, mainly 14X Pacer and 15X Sprinter units of 1980s vintage. The Pacers – and some of the Sprinters -do not comply with compatibility rules, and new build is not an option due to tougher emissions standards; hence the attraction of conversion.
The ‘D’ stock (short for ‘D78’) was built between 1978 and 1981 by Metro-Cammell, Birmingham, for the District line and consists of 150 3 car units (which normally double up as 6 car sets). The interiors and exteriors were completely refurbished between 2005 and 2008, and new Adtranz bogies were fitted between 2000 and 2003. The ‘D’s have achieved very high levels of reliability and availability. Each carriage has four large doors per side, which permits low station dwell times of around 20 seconds.
Allan Dare for Vivarail explained:” Our plan is for a three car diesel-electric multiple unit, using ‘upcycled’ mechanical parts to avoid new construction regulations. We would use diesel engines under each end driving vehicle and locate the generator unit beneath the middle car. Our proposed Class 230 would have a maximum 60 mph top speed, but have better acceleration than existing trains. This, combined with an estimated 17 second time saving at each station stop, should reduce overall journey times (especially if many stops are closely-spaced together).
“A wide range of options are available: two or four doors per carriage side, transverse or longitudinal seating, space for cycles, luggage, plus a more generous circulating area. It will be fully PRM-TSI compliant. The D train would have 10% to 25% more capacity than a Class 150 ‘Sprinter’, and between 35% and 80% than a ‘Pacer’. It uses proven technology, is reliable and easy to maintain. We envisage a fleet of around 100 3 car units and they could be in service from the last quarter in 2015 onwards.”
Richard Hammerton for The Yorkshire Train Company outlined his alternative proposals: “The ‘D’ stock are being displaced from the London sub surface lines not on account of their age or condition, but because more additional capacity is required by TfL. They are good vehicles and not life-expired. We propose using four- car (Class 278/4) and two-car-version (class 278/2) variants. The 278/4 will have an above chassis Cummins QSX15 675hp Tier 4 compliant diesel engine at each end of the train. Transmission will be electric.
“Our Class 278/4 will accommodate 180 seated and over 500 standing passengers. It would be suitable for driver only operation. The vehicles were designed for LU operations with electrical controls duplicated to minimise the risk of failure. Downtime is about four or five times less than that achieved by ‘Pacers’ or ‘Sprinters’. The 278 is essentially the same electrical unit as the D78 and we can gain benefit from the technical expertise, as well as from the supply of important component parts.”
Commenting upon the (above chassis) position of the engine, and the rival Vivarail project, Hammerton added: “Our vertical layout with the engine over the bogie is the best position since putting it underneath the centre of the vehicle would provide enormous bending stresses; it also makes it easier for maintenance. 1,300hp in a train weighing 120/130 tons provides about 11hp per ton. The Vivarail project is light on detail: The closest engine providing a similar power to weight ratio would be the MTU V12, but it would be too big to go under the floor so they would have to settle for something less powerful with about half the power-to- weight ratio we are proposing. When Vivarail starts doing some reasonably serious design work, they’ll discover that their proposal doesn’t work.”