Deep thinking

The Tube has been transformed in recent years thanks, in no small part, to Bombardier’s innovative trains and Transport for London (TfL) will doubtlessly be hoping the New Tube for London (NTfL) project will bring about an equally significant change. 

Bombardier hopes to win the contract, and firmly believes it has the capability and capacity to deliver what would be the biggest deal of its kind, and one that is set to revolutionise the London Underground network. 

This project is a matter of necessity, not vanity, for London. The Capital is growing rapidly. By 2031 there will be an extra 1.8 million people living and working there. Every three days, about 800 people move to London - slightly more than the average Tube train capacity, by coincidence.

By the 2020s the Bakerloo, Central, Piccadilly and Waterloo & City lines will be operating some of the oldest trains and signalling on the Tube. These combined factors have steered TfL’s approach to the development of a programme for a comprehensive modernisation of these ‘Deep Tube’ lines. 

There is strong and growing demand across the whole TfL rail network, including the Tube, London Overground, Docklands Light Railway and the trams, so the new Tube trains will need to address the need for ongoing increases in ridership and service frequency, with technology requirements not just for today, but for decades to come. On December 4 2015, LU carried 4.821 million passengers on the Underground - the most in one day. That week was also the busiest in the Tube’s history, with 28.76m passenger journeys. That beat the previous total of 28.69m, which itself was set in the week ending October 31 2015. Additionally, TfL says that 18 of its 20 busiest days ever on the Tube network occurred last year. The second busiest was November 27 2015, with 4.795m, while third was October 9 2015 with 4.375m. Fourth was November 28 2015 with 4.734m while fifth was October 29 2015 with 4.719m passengers. 

These figures illustrate the sheer scale of growth in usage. Overall, demand has risen by a third since 2001, with the rate of growth accelerating significantly in the past five years. 

Nick Brown, LU’s managing director, said: “The Tube continues to break records for the number of customers it’s carrying, as London’s economy and population keeps on growing. The vast majority of the busiest days in the Tube’s 152-year history have been recorded this year .

“The current work to improve London Underground is one of the largest programmes of infrastructure investment in the world. We will continue to invest all our income in modernising the service, improving reliability, train capacity and frequency, and upgrading major stations to provide a Tube network fit for the capital city it serves.”

Already trains run more frequently and reliably on the Victoria Line, where Bombardier’s 2009 stock has helped TfL to increase the number of trains per hour from 32 to 36 this year.

Overall, because of the modernisation on the Tube network, TfL claims that journeys are now quicker, that there is an average reduction of around two minutes per journey and that delays have decreased by 40% in recent years.

TfL says: “Further upgrades are ahead, with new air-conditioned trains now serving the Metropolitan, District, Hammersmith & City and Circle lines, new signalling planned for those lines, and the radical modernisation of the Central, Piccadilly, Bakerloo and Waterloo & City lines in the 2020s. Major work on the Northern Line extension to Battersea started in November 2015, which will support thousands of new jobs and homes and enable major regeneration in the Vauxhall, Battersea and Nine Elms areas.”

TfL has highlighted the ongoing priorities regarding the Tube which fall into four categories: safety and reliability, maximising capacity from the existing network, growing the network and meeting the growing expectations of its customers by providing excellent customer service.

The aim will be to achieve a steady state of renewal, where modernisation is a continual process that is built into the everyday operations of TfL. 

The first line to be rejuvenated under the New Tube for London programme is expected to be the Piccadilly Line. 

TfL admits the Edwardian-era tunnel infrastructure presents a massive challenge to the planned NTfL modernisation programme. The tunnels were not designed to dissipate increasing levels of heat from traction energy, leading to a steady rise in tunnel and station temperatures since the lines opened in the early-1900s (see feature on pages 100-103).

Bidders will be expected to address these constraints while introducing air cooling and other features expected by today’s passengers. Such challenges are compounded by the confined Deep Tube infrastructure which includes 3.5m diameter bored circular tunnels, cast iron tunnel linings and the line topography. The tight curvature of some track sections in the central London areas reflects the arrangement of the street plan above ground. The fixed length platforms and their depth below ground, as well as struggling ventilation systems, will also have an impact on what can be achieved from a capacity enhancement point of view. However, TfL believes bespoke and unique applications for key assets such as rolling stock can get results.

Talking about the NTfL scheme, Bombardier Head of Bids Engineering Niall Simmons says: “This project is for the Deep Tube rather than sub-surface lines. And, therefore, it requires some unique technical solutions associated with both the design and operation.”

So what are the constraints? Is it a case of Bombardier looking at the products it has on the network currently, the Victoria Line which runs in the Deep Tube and the sub-surface S-Stock that has air-conditioning, and fitting the latter’s capabilities in the former? Essentially the answer is yes, but there’s a lot more to it than that. 

Says Simmons: “These trains have to fit into ten foot four tunnels. 

“As you know, S-Stock has air conditioning on the roof and wide gangways. I’ve got a picture that shows that a Victoria Line train would fit inside an S-Stock train. So the roof space isn’t available for Deep Tube vehicles. As an engineer you have to be very innovative in terms of where you locate equipment and how you locate it, while still making it reliable. There’s an art in doing that. We’re in a fortunate position. We know the characteristics of the infrastructure. And we understand how it is operated.”

This experience is garnered from the Victoria Line and S-Stock fleets. Says Simmons: “We know the infrastructure very well from the years of testing and operation of our trains on it, and from studying the feedback for these vehicles. It isn’t through luck that the S-Stock and Victoria Line fleets have been made so reliable. 

“The most important consideration for the design and manufacture of the NTfL fleet will be to ensure that - even after the incorporation of cutting-edge technology and novel features - the vehicles are extremely reliable from day one.” 

Because of its experience, Bombardier is confident of achieving that goal. It has the experience of the LU network that, arguably, its rivals do not. The last non-Bombardier-built trains were delivered to London Underground in 1995 - 21 years ago, and during that time a lot has changed.

Simmons says of the NTfL deal: “The project stipulates articulated vehicles. We have experience of producing them across the world. TfL wants high passenger capacity, so it’s also about optimising space in the vehicle. That is where our global experience of articulation can and will help Bombardier.” 

He says: “London Underground wants to move as many people as it can with maximum efficiency, and without increasing tunnel temperatures. At the same time, passenger comfort must be improved.” 

This must also be done while making the experience pleasurable for the passengers. The design is vital to this, says Simmons. “TfL are looking for an iconic design for this particular train. They’re thinking about the passenger environment and about maximising capacity. This project will represent an engineering challenge, but Bombardier has gained two million engineering hours of experience working on TfL projects, which we aim to use.”

The number of vehicles will, of course, also dictate the capacity offered. The formations will vary, according to the maximum platform length on each of the lines set to receive new trains.