David Brignell, senior fleet manager at Transport for London (TfL), is responsible for the running of the fleet, which is based at the Old Oak Common depot in West London. The previous railway yard was completely rebuilt for the Class 345 fleet. “Procurement of the fleet and the depot were done together – and that’s very rare,” says Brignell.
“We knew what we were trying to achieve: the number of trains a day and where they would operate. The site has enough physical space, and stabling for a large percentage of the fleet on site. That makes operational decisions easier.”
He adds: “The unit was designed so there wasn’t a tremendous amount of routine maintenance required” – the typical inspection interval is 105 days – “and it’s very straightforward and well-managed. Obviously as the train ages there is some overhaul activity. More of the effort is looking at system performance and reliability, so we don’t have that cycle of fault/repair.
“We made the market aware that in order to win this work the cost of maintenance would be a very significant part of the assessment.” TfL didn’t specify particular solutions, the senior fleet manager points out: “It was output-based. We were encouraging the market to provide us with the design that had the lowest overall lifecycle costs.”
For example, regenerative braking takes up most of the braking effort, dramatically reducing wear on brake pads and discs. “We’re not there yet – you’ll have to ask us in ten years’ time whether it’s worked out as we predict!”
“We offered the market a very long certainty of work. Whereas other operators might procure for five or seven years, we procure for the life of the vehicle, and that enabled the market to think about it completely differently.”
Brignell says that, similarly, the depot was specified so that it wouldn’t need a fundamental upgrade in a few years’ time, with spare capacity or ‘passive provision’ in case more or longer trains are specified: “We’re looking ahead 50 years-plus.”
In addition, an automatic vehicle inspection system (AVIS) was a key part of Bombardier’s (now Alstom’s) maintenance strategy. “Because we have so many units stabled here it’s a very productive piece of kit”. AVIS combines cameras, lasers and wheel loading equipment to look at the underframe, the wheelsets and the brake pads, while body side cameras check the aesthetics of the train – graffiti, for instance.
“TfL has set a very high standard for the aesthetics of the fleet,” says Brignell. “The units are cleaned every day and deep-cleaned every month, and that’s a big cost to the operation as compared to the routine maintenance”. The depot’s two massive train washes can each handle 12 trains an hour.
“On the roof, cameras are looking for anything untoward, and more importantly the condition of the pantograph [which picks up current from the overhead line]. This aids us with reports of problems in service or problems with the OLE [overhead line equipment]. It gives us a snapshot of the train’s condition every day.”
However, it’s purely a monitoring system: “There’s no repair action done through AVIS,” says Brignell. “But in addition, the train management system monitors thousands of inputs from the different systems on the train, and it will report remotely any problems that require attention”. TfL has technicians in a control room 24/7 who can help with drivers’ enquiries and interface with the train management system in real time. “It’s about early warning, so we can plan. When the train comes in we pretty much know what needs doing before we look at it. Traditionally on the railway some of the monitoring was done by the lineside, but “We don’t rely on anything from anybody else anymore.” In fact, Brignell adds, “three of our trains monitor the infrastructure itself – those trains will look at the forces on the OLE, for instance – and we can report back to Network Rail. We specified the train so that it’s completely self-sufficient.”
Similarly, “the decision we made was that the train crews would do what they do best, which is to drive the units. We can do a train prep faster with a technician than a train crew, and we can do it better, more consistently and we have someone there to take any intervention if it’s needed. It’s about maximising availability and fleet utilisation.”
BOX: THE CLASS 345
The trains in operation on the Elizabeth line are the Class 345 ‘Aventra’ electric multiple units. Seventy of these nine-car trains, each carrying up to 1,500 passengers, were built in Derby by Bombardier Transportation (taken over by Alstom in 2021).
The Class 345 is 205m long, with a weight of around 319 tonnes. It has 18 two-axle bogies in all, ten of them fitted with electric motors for a total rated power output of 4,400kW. The power comes from 25kV, 50Hz overhead lines via a roof-mounted pantograph, while the braking is a combination of regenerative braking through the motors and air-operated ‘electro-pneumatic’ disc brakes.
The aluminium body is built to the latest crashworthiness and fire standards. “Everything on the train is effectively modular, so can be replaced,” says David Brignell. The trains incorporate three independent signalling systems, for different parts of the network: this complexity is one of the reasons for the modular design. Another is the extraordinary expected service life of the units: at least 35 years, and possibly 50. “There’s not a lot that will see them scrapped,” Brignell says.
BOX: WHEEL MAINTENANCE
Inspecting and repairing wheels is a major part of the work at Old Oak Common. “We can lift a [nine-car] unit completely up to remove the wheelsets and bogies,” says David Brignell, “and two of the roads have a drop pit arrangement: you can drop the bogie, and it goes underground and pops up in the stores.”
In keeping with the philosophy of keeping capabilities in-house, the depot has a double-headed Hegenscheidt-MFD wheel lathe (pictured above), which can turn a complete bogie at once. However, says Brignell, “We turn only when we have to and as little as we have to, to protect the life of the wheelset.”
The train’s WSP [wheel slide protection] system helps prevent sliding (like ABS) to avoid damage from overheating, which can harden the steel and lead to cavities. Meanwhile, lubricant is deployed directly on to the wheelset in operation; it is programmed to spray only at key corners and radii, reducing wheel squeal and wear.
BOX: A YEAR AT NEVILLE HILL, WEST YORKSHIRE
Train operator Northern celebrated the first anniversary of its takeover of Neville Hill TrainCare Centre on the outskirts of Leeds in October.
Northern became the sole operator of the facility on 17 October 2021 and set about transforming the massive depot into a catalyst for change.
Jack Commandeur, engineering director at Northern, said: “TrainCare Centres like Neville Hill are fundamental to the daily operation of the UK rail system. Although geographically well defined, their impact on the railway system and its supply chain are far-reaching.”
Every day, a team of engineers and support staff at Neville Hill service 34 trains from nine different fleets and carry out more than 500 safety and service-critical tasks. Its work supports 260 direct and 825 indirect passenger services a day.
Commandeur added: “We inherited a tremendous team and we’re now working together in a focused and consistent way on a single vision and strategy for the site that can be implemented for the benefit of all, and subsequently the customer.”
Since it became sole operator, Northern has completed a site-wide clean-up, integrated teams for more efficient working, improved security, refurbished facilities for staff and improved safety with the installation of illuminated walkways. The Neville Hill team also shared learnings with other TrainCare Centres across the country with an ongoing programme of depot visits.
And the work continues. Northern believes a transformed Neville Hill can benefit not only their customers, but the local community too. While customers will benefit from better maintained and more reliable trains, the local community will have access to employment opportunities supported by training and apprenticeships.
BOX: GREEN HEATING AND COOLING
Energy saving was a major criterion in the design of the new depot, and part of the planning requirements. Taylor Woodrow incorporated a number of measures to reduce emissions, including solar thermal panels for water heating (rainwater is harvested and recycled), 1,500m2 of photovoltaic cells on the roof and an underfloor heating (and cooling) system, supplied from a system of ground source heat pumps. These are connected to 366 geothermal piles and 52 boreholes, which are up to 150m deep. Most importantly, the multiple systems are connected by an energy management system which can switch between energy sources as required.