Joe Bednall stands in the middle of Bombardier’s Litchurch Lane site in Derby looking at the steel frame of a gigantic building under construction. “It’s beautiful isn’t it,” he says with a smile of contentment. “This building is a real statement of intent. It’s confirmation that train-making on this site has a long-term, sustainable future.”

The steel shell will soon become a test and commissioning facility for several hundred electric train carriages that Bombardier is supplying for the new Crossrail link in London. The first full train is under construction, and will be finished by the first quarter of 2016, and tens of millions of pounds have been spent at Derby to underpin the contract. 

“It’s all systems go,” says Bednall, commercial director at Bombardier and deputy head of the firm’s Crossrail project. “The first half a dozen trains will be on a slow build to ensure we get everything right. Then we will start to up the tempo and the trains will really start to roll off the production line.”

The £1 billion contract between Transport for London (TfL) and Bombardier covers the supply of 65 nine-car 25kV, 50Hz electric multiple units, branded Aventra by Bombardier and allocated Class 345 in the national numbering system. The publicly released specification includes a passenger capacity of 1,500, with 450 seated in a train no longer than 205m with a top speed of 90mph (145km/h), and an energy efficiency as good as 24kWh per train-kilometre. 

Key features include air conditioning and interconnecting walk-through carriages. The aluminium shell trains, combining low weight and high acceleration, will be built with an emphasis on energy efficiency, and will feature intelligent energy management systems. 

The trains include in-cab signalling/communication including satellite and ERTMS level 3 technologies and regenerative braking, offering low cost of operation and high reliability, says TfL.

From the outset, Crossrail has insisted that it did not require a revolutionary design, preferring instead to opt for a fleet based upon mainly existing technology already developed by the international rolling stock sector for deployment on other rail networks. Bednall confirms that this has been a guiding principle since the original pitch for the work.

“Crossrail were very clear on this,” he says. “It was not expecting a rail revolution on this job. It was keen to ensure that whatever solution we put forward was deliverable. So from our point of view it was evolution rather than revolution. There was no need to start off back at the drawing board.”

The solution was the Aventra, an electrical multiple unit that Bombardier’s engineers say will offer significantly reduced weight, optimised energy consumption and low maintenance costs when compared with current UK best-in-class EMUs. The aim has been to deliver a highly modular platform that can be used first for the Crossrail project, but then be easily modified for different market requirements, ranging from a 90mph metro train to a 125mph intercity express. 

The interior and plug-and-play systems will enable operators to change elements throughout the life of the train, from mid-life upgrades to weekly interior re-configurations to match demand. Even fundamental elements, such as the layout and length of each carriage, and the number of doors, can be altered within the framework of the core Aventra design.

Design future-proofed

“We wanted to establish a platform from which we could pull future derivatives off,” says Bednall. “So in this case, the shell is Aventra – but the systems that make up the design specifics are unique to Crossrail.” 

On the Crossrail project, low weight and energy consumption were crucial factors in early-stage considerations. The main determinant of energy use is the mass of the train, with Bombardier opting for lightweight aluminium body shells combined with an in-house bogie design that is claimed to offer 30% reduction in total bogie mass and unsprung mass compared with conventional designs. 

“We put a focus into all the supply base to bring down mass whenever they could,” he says. “We’ve put that challenge to them all the way along the line on the Crossrail project.”


Lightweight: The Flexx Eco bogie

The bogie selected was the Flexx Eco, an established product that has notched up many millions of miles on Bombardier’s Voyager and Meridian fleets. The Flexx Eco features an inboard bearing design which, coupled with a smaller wheelbase and hollow axles, brought weight reduction and improved aerodynamic efficiency, boosting energy efficiency. The inboard bearing design also allows for ease of maintenance, with improved access to the wheels and brakes. The bogie’s lower unsprung mass leads to less wear on the track.

The first of the aluminium shells, comprising underframes, bodysides, roofs and ends, have been bolted together at the Derby site. Meanwhile, in an adjacent facility, complex electrical looms that will be fitted on-board are carefully woven together by hand. Bombardier has opted for a dual-speed approach to the design and construction process. So, while the body shells are in production, the designs of other systems and components are still to be signed off. With the first train not due for completion until early next year, Bednall thinks this is a sensible approach. 

“We’ve gone for a slow, staggered build process on the first few trains,” he says. “So while underframes, bodysides and roof sections have been delivered to the line, we are still in the design stage for other systems. The interior, for instance, will come a lot later. We don’t need to be taking receipt of seats now. We want a slow and methodical build-up of production.” 

That’s not to say that little consideration has been given to how all the requisite systems and components will fit together. Far from it. Bombardier has invested £1.6 million in its Train Zero concept – an ‘iron bird’ facility where advanced pre-production testing of the electronics and systems can take place in a simulated environment and at a much earlier stage in the design process than was previously possible. 

Train Zero has been conceived to drive out integration problems that previously would have been identified when the first train was built. Ultimately, it should deliver more reliable trains and improved performance.

Leap of faith

Train Zero is the brainchild of Mark Ellis, Bombardier’s head of engineering, strategic projects. “It’s a very novel approach,” he says. “I’m not sure anyone else has done it in this industry. We are really trying to de-risk everything as early as possible. It’s a big investment of time and money. And it’s a bit of a leap of faith too. But it will prove invaluable.”  

Train Zero is effectively a ‘debugging’ facility that is used to ensure that all the various on-board systems and components can talk to each other without fault. So, when the first train comes off the production line, it should work perfectly from the outset. There should be no unknowns.

In line: Carriage panels await assembly at Bombardier’s Derby works

Bombardier has started to test the first batch of systems within Train Zero, and it has already highlighted technical glitches that previously would have gone unnoticed. “With the sliding doors, for instance, we found a wiring problem which we wouldn’t have seen until they were on the train,” says Ellis. “Once the train is built, it takes a lot more time to establish where a problem has come from. Once it’s built, there’s confusion about whether production have put it together correctly. Now, with Train Zero, we can take that uncertainty out of the equation.” 

One suite of technologies that will work its way through Train Zero is a set of prognostics and diagnostics tools that will be fitted to the Crossrail trains to provide condition monitoring data. The doors, for example, will be fitted with sensors to flag degradation in performance. Realtime data can be recorded and sent back to the maintenance depot, where technicians can prepare replacement parts in advance of any failure. 

“We’ve put in a system called tele-diagnostics which allows us to change certain parameters while the train is in operation,” says Ellis. “That will allow us to perform live investigations. We will be able to do that fleet-wide or on a specific train. We also have a human-machine interface mimic – meaning that the maintainer can have a live view of the train driver’s screen to see what is going on. The maintainer will be able to watch a driver to see what buttons he is pressing and in what sequence. Sometimes we see faults because drivers are not doing something right.”

Checks for wear and tear

At the maintenance depots, the Crossrail trains will pass through what’s being called an automated visual inspection system (Avis) – a loop of sensors, lasers and cameras that will scan certain parts of the train, measuring and recording data for comparison purposes. “The next time the train passes through Avis, the system will be able to see if there has been excessive pad wear, or if the pantograph carbons need replacing, even if a bolt has moved,” says Ellis. “The train comes into a depot and simply passes through the hoop, comparing the current to last state of its condition.”

Ellis says that the aim is to move away from scheduled maintenance and into condition maintenance. “The vision is getting us to the point where we don’t have to touch the train anywhere near as much as we used to. We’re not going to say we are going to inspect, say, every 30,000 miles. We might decide not to inspect at all. Because the trains will tell us when they need inspecting. That’s true condition-based maintenance.”

When each train is finally built, it will enter a new £12.5 million testing facility which is nearing completion on the Litchurch Lane site. Here, 205m trains will be able to sit side-by-side on raised floors, enabling technicians and maintenance teams to ensure they meet all performance specifications set out by the prime customer, Transport for London. The building is cited as physical evidence of the renaissance of the Derby plant. It is a reassuring indication that Bombardier’s Canadian parent company is happy to invest in the facility, confident that future orders for trains to service commuter routes in the UK are in the pipeline.

Initially, five full Crossrail trains will be built, at a slow, methodical pace. The first was started in June and will be ready next February – almost nine months later. Within a year or so, a production drumbeat will result in each train taking less than three months to build.

So far, the construction effort is going well. “We are where we said we would be at this point,” says Ellis. “We haven’t missed a milestone payment, and we are now quite some way into the project.” Bednall agrees: “So far our lords and masters are very pleased with us,” he says. 

When all 65 trains are built, Bombardier will enter a 32-year contract to look after them. A new maintenance depot is being built at Old Oak Common in north-west London. “It will be our job to put them into service every day, and to keep them running,” says Bednall. “If there are any problems with the trains in traffic, then they are our problems.

“There’s a very onerous penalty regime, as you would expect. If these trains are delayed in that central section, we feel a lot of financial pain.”

Lessons learned from problems with Victoria line doors

The introduction of new classes of rolling stock always causes unexpected technical issues. That was true of the 2009 Tube stock, a type of London Underground train built by Bombardier as part of its Movia family. A total of 47 eight-car units were built for the Victoria line, entering passenger service between July 2009 and June 2011 and replacing the 1967 Tube stock.

While the fleet has since gone on to record excellent reliability statistics, in the early days an over-sensitive door edge mechanism caused significant delays. Eventually a reworked mechanism, dubbed the Intelligent Sensitive Edge, had to be developed to overcome this problem at a cost of £3 million across the fleet.

Joe Bednall, commercial director at Bombardier, smiles ruefully when the door edges are mentioned. But he says he is prepared for such issues with the Crossrail trains. “All I will say on the door front for the Crossrail trains is that we have selected the very best-in-class door system supplier – IFE in Austria.

“When I went out there to look at their testing facility I was flabbergasted at the range of conditions they had applied to the doors. There were test beds looking at the doors opening in normal conditions, ones with trains passing causing pressure pulses, others were dirty and full of grit – every conceivable scenario was there with doors hammering backwards and forwards on these test cells.”

SPOTLIGHT: Bombardier's Derby plant 

Bombardier’s Litchurch Lane works (formerly Derby Carriage and Wagon Works) was built by the Midland Railway in the 19th century. The plant has produced rolling stock under the ownership of the Midland Railway, LMS, British Railways, BR Engineering, ABB, Adtranz and now Bombardier.

Order pipeline looking good for Derby plant

Bombardier’s Litchurch Lane works in Derby is currently supplying London Underground with 191 new air-con trains for the Metropolitan, Hammersmith & City, Circle and District lines, as well as extra carriages for London Overground to increase the length of its trains from four to five cars.

The Crossrail contract will keep production lines busy for the next three years, but Bombardier is actively seeking other orders. There is limited export potential for the Crossrail platform, because of the peculiarity of the UK’s gauge set-up, but Bombardier is confident of winning orders for Aventra derivatives to serve commuter routes across the country. “When we started work on the development of Aventra, we did a lot of research and the forecasts showed that there is a potential market for 2,000 cars over the next 10 years,” says Mark Ellis, head of engineering, strategic projects. “So we still hope there are a lot of opportunities to come for trains based on the Crossrail platform.”  

Specifically, Bombardier is hopeful of winning a deal to provide a fleet of at least 39 electric trains to Transport for London to operate on some of the West Anglia mainline routes that have transferred over to TfL, as well as on the London Overground route between Barking and Gospel Oak.

Bombardier is also confident of winning work on contracts to supply three state-of-the-art electric train fleets for the Thameslink, Southern and Great Northern franchise.