The Crossrail project is truly large scale. It provides vital capacity for east-west links and accessibility into central London and core business districts, links with the London Underground and improves connectivity of Great Western, Great Eastern and South East sections of Network Rail. The link is 118km long from west to east and will have a capacity of more than 200 million passenger journeys a year. The central section will run 24 trains an hour (average every 2.5 minutes) in each direction and for the most part will be underground. More project statistics include the construction of 42km of tunnels, 37 new stations including eight sub-surface, more than 60 lengthened platforms, the removal of eight million cubic metres of spoil and 140 main works contracts. The total infrastructure budget is GBP 14.8bn (USD 23bn).
To accommodate the planned passenger capacity in the central section, the trains will be larger than those on today’s underground system, with each extending more than 200m and requiring tunnels with a diameter of 6m. In comparison, the Victoria line tube tunnels are 3.81m in diameter and the Channel Tunnel some 7.6m. Eight TBMs are constructing tunnels up to depths of 40m below surface.
The majority of the geology of the central section is London Clay, a stiff blue-brown clay that underlies most of central London. Below this is the Lambeth Group – up to 20m of sands and clays, the Thanet formation – up to 16m of fine sand and the underlying chalk. In the west of the central section, London Clay is dominant from the portal at Royal Oak through Bond Street, Tottenham Court Road and Southampton Row (Fisher Street), beyond which an anticline brings the Lambeth Group nearer the surface and where the tunnels will follow the approximate boundary between the London Clay area and then this group.
Further east, the Millwall anticline brings the Thanet Sands of Palaeocene age (54.8-57 million years old) near to the surface, while at the Victoria Dock portal the tunnels are back into London Clay. On the south side of the Thames, the North Woolwich portal takes the tunnels into the Chalk to Plumstead and into the Thanet Sands at Woolwich Station.
When tunneling in an urban environment, the prime consideration is to ensure zero ground settlement, which can affect the structure of the buildings above.
TBM development has led to shielded machines that can extract and transport spoil at the same rate as tunnel advancement – called earth pressure balance machines. Six of these will be used in the central section, while two machines used within the chalk will be slurry shield TBMs to cope with soft ground and high water flows in the section between Plumstead and North Woolwich.
The method of lining the tunnels is partly determined by the geology resulting in a mix of sprayed concrete lining (SCL) and bolted pre-cast segments, the latter being cast at tunnel portals with the first plant built at Old Oak Common, near Acton in west London.
The tunnels are not the only underground constructions for the project. Bigger stations are required to accommodate the larger trains that will run on Crossrail and to meet the projected capacity a fleet of 65 new trains is required, each with a capacity of 1,500 passengers. Power for the trains will be via 25kV overhead cables and will support faster accelerating and braking.
A braking energy recovery system will be built in that will reduce heat generation in the tunnels. With increased passenger loads over current underground trains, the design engineering has to maximise the passenger flow in and out of the carriages.
Congested underground
The construction of larger stations has been an equal challenge. In the central section, the historical legacy of London’s sewer system, water and electricity supply, large building foundations and the Tube lines have created difficult civil engineering environments for Crossrail. This is compounded by the established interconnections with existing underground and surface stations that are often in crowded parts of the city. An example of the challenges can be seen at Tottenham Court Road where the existing station, built as two separate tube platforms more than 100 years ago now hosts 150,000 passengers’ journeys daily. Crossrail will add to this a new station with 260m underground platforms at 25m depth; a new eastern ticket hall on Dean Street, escalators to the existing Northern line platforms and a new ventilation shaft.
The ‘box’ containing the new Crossrail station and interchange facilities all have to be built on a much-expanded footprint confined by Centre Point and Charing Cross Road. On site are a huge amount of facilities buried just below the surface, making the job extraordinarily difficult and requiring diversions at street level in and around Charing Cross Road and Oxford Street. The ‘box’ is constructed of reinforced concrete base and perimeter walls.
RCC
The role of Route Control Centre (RCC) is to control the trains and infrastructure of the central section and also to ensure seamless integration of Crossrail services with the Great Western, Great Eastern and South East parts of Network Rail and the London Underground network. This integration of new and existing systems is an enormous challenge. All facets of service operation are governed through a suite of Crossrail-specific operational concepts, which direct operations, safety and maintainability. Moreover, these ultimately determine how the performance, capacity, the command and control and the operational interface with other infrastructure managers are provided.
One of the major challenges within the project is combining existing network services, with the high-frequency mass transit systems that Crossrail will provide. This includes the traffic management challenges of delivering a railway that will have to interface to existing timetabled, governed routes that at the same time ensure, where possible, even headways through the central operating section.
In late 2012, Crossrail let a contract to a consortium comprising Siemens and Invensys Rail to install a communications-based train control (CBTC) signalling system for the central operating section, which controls the section linking Portobello Road in the west, Pudding Mill Lane in the east and Abbey Wood in the southeast. This system will allow the control of trains that will take into account the possible delays and gaps between trains by automatically adjusting their speed through a series of interlocking control systems, fixed position and on-board train position reporting and movement authorities for each train, determined from central controllers that have interlocking interfaces.
The driver has in-cab signalling equipment and displays and features such as automatic train protection, automatic train operation and automatic train regulation will be provided, including trackside reporting of train position. As the number of trains per hour in the central section will be far greater than those on the Great Western and Great Eastern Network Rail sections, it is planned that there will be an automatic train reversal system of up to 14 trains per hour beyond Paddington at Westbourne Park.
Three control centres (Great Western, Central and Great Eastern) will manage Crossrail services and integrate with London Underground and Network Rail. Crossrail has already made a model for control centres that will allow functions of supervisory management, signalling and regulation, engineering management (of fixed equipment, such as power and ventilation), train management and customer services control. While the new RCC control centres provide new, integrated control and operational management.
It’s important that centres do not risk unwarranted distraction between safety and support roles and that the need for a back-up control is also addressed. Integrating Crossrail is a complex problem, but when the central operating section is operational in 2018, it will provide 10 per cent additional capacity for east-west travel in central London.
Questions and Answers
Question 1
As a member of Min South, I am not as familiar with all the aspects as our tunnellers here, but the one thing I was just wondering is the disability access and how that is built in, particularly with 24 trains coming through an hour and some very busy places and people coming in from Heathrow or shopping in Oxford Street, so my question is how is disability access built into the systems?
Gavin Bowyer, Min South
Answer
Disability access is fully designed into all the new stations. It’s fully useable for passengers with restricted mobility on all the new stations. There is a huge amount of work being done. One thing I didn’t include because of timing, I took a slide out about what is happening on the network.
Building new stations is relatively easy, to make sure we have lifts, but there is a lot of on-network work being done. We have 37 stations across the route and there is a huge amount of on-network work being done by Network Rail.
There is GBP 2bn (USD 3.1bn) worth there. There are a lot of works ongoing to do the station upgrades to achieve that, but for all the new stations, the new Central Section Stations, Sub Service Stations, all of that is engineered in, but it’s not just about lifts and escalators, it’s about level access into the trains, it’s about the design of the trains, so from the full end to end of accessing to egressing the individual’s journey on the Crossrail route.
Question 2
Just a follow-up to that question on the disability issue. If you could just imagine a passenger, say getting on at Maidenhead, wanting to go to some station that’s not an actual Crossrail station, but at some station on, say, the Northern Line where it may not be fully accessible at the moment, will there be a system in there, that a passenger getting on at one of these other stations can readily appreciate his whole route. So will there be a proper information system that will be able to alert that passenger before they board the train?
Mike McConnell, retired from Balfour Beatty
Answer
The short answer to that will be, yes. The Crossrail train operator, which will be appointed relatively shortly, will ultimately be responsible for the whole information provision to deliver that and they will have to own both that level of information, but also to handle specific individual requests and even to look after them.
I’m thinking about blind access and having people to meet, but in order to do journey planning – we want it to be quite a smart railway and we want to think how much technology do we want, but putting that aside because of course we all expect various apps and things to be there, but to be able to provide that information or get that information, be it from a help point on arrival at the station, perhaps having some sort of smart kiosks to identify where you want to go and whether or not, if you have some mobility issues, how that will be delivered.
Question 3
A question about the operator. Crossrail is going to be appointing the operator – is that correct and when and what’s the process, particularly in light of a little bit of difficulty that perhaps DFT, who have done this sort of thing before, have had recently with appointing operators.
Mike Napier, Costain
Answer
I will answer what I know. The operator will be multiple. The infrastructure manager for the central section will be Rail for London so they will maintain the rail, the signalling and such like and they will also operate signal and provide some of those core safety roles I have illustrated in the Route Control Centre, so there will be an operator there. The operator, the concession that is going to be let for the Crossrail train operating company, that is being done over the next two years relatively quickly, because the first time you start to see Crossrail will be when that TO C starts to take over on the Great Eastern.
I am not the expert here, I will tell you what my best understanding is, and that might even be before the new trains arrival or in parallel with that and services with eight car units, rather than probably 10 that we will have will then operate and just replace the existing service today into Liverpool Street. So the second part of your question, which I almost certainly can’t answer, all to do with the sort of politics and the conflicts, and of course it’s been hot in the press with what’s been happening out on the Great Western. I’m your engineer, not an end engineer, thank God.
Question 4
I have a simple question; will passengers be able to use their mobile phone to access voice services and the Internet?
Nick O’Reilly, Min South
Answer
It would be sinful if they couldn’t. However, there is no contract at the moment to deliver that, but I can’t imagine it opening without that. There are discussions ongoing – I mean of course it’s a matter of who can pay for it and that sort of thing. There are some conflict issues with what’s happening.
I mean you’ve got that today on the Heathrow lines, but the various upgrades on one of the GSMR are… you know there’s issues, engineering issues, technical issues being looked at because everyone will want 4G but we are not going to be getting into Crossrail for another five to six years.
It’s going to open in stages – I was told not to put any stage opening slides up tonight, but we are not going to be up and running on the central section until about the end of 2018 or early 2019. It’s still a number of years off and 5G will probably be talked about. Just talking personally, it would be highly surprising if it was not provided, because we are dealing with business travellers going into Canary Wharf, into Heathrow and the like.
We’ve got these, what my son calls "first world problems," with people wandering around using their phones perpetually and I do it and I don’t like other people in front of me doing it, but we all do it and we all expect it. It’s the way of the world.
Question 5
At the Transport Asset Management Conference held here in London last November, a presenter from the European Rail Agency gave a presentation on the challenges for European rail integration and, perhaps rather unfairly, held up Crossrail as a bit of a lost opportunity. His way of presenting it was that it was going to be another railway with its own rolling stock and its own requirements and its own signalling flavour of ERTMS and taking European standards as inspiration, but not necessarily fully applying them.
I just wondered if you had anything to say about that.
Adam Noakes, Mott MacDonald
Answer
We have had to take concessions and dispensations from the European Community to do what we’re doing. We’re doing the right thing to manage our risk and our requirements when looking overall at what Crossrail has to do in terms on any operability, so it was getting concession to make sure we didn’t incur costs or risks that the project wasn’t prepared to take on board. Ultimately we’re building a new railway and we have all those rules out there so why aren’t you complying with them? A lot of people worked quite hard and sort of delicately on that. Ultimately we had a sort of robust case to put forward.
Question 6
You spoke a bit about responsible procurement and you mentioned apprenticeships, so my question is about local supply chains and I don’t know whether you can comment about what you experience in that area. Whether you are able to find any success stories around this area within the works packages that you spoke about or just generally your experience of having to deal with requirements for local supply chain from TFL especially.
Jillian Lilico, Demeter Development
Answer
That is a question that I can’t answer, but I can put you in contact with people that do. I am not aware about the local supply chain having to engage there. We certainly have to engage and promote local workforce. My knowledge is from my own sort of systems area. We take questions, but I can’t take on board not to answer them personally, but if you wanted to know an answer to that question, I could put you in touch with people that can help. I said at the beginning of the presentation that I am who I am and Crossrail is massive in every which way, whether it’s in engineering or in a commercial activity.
Question 7
You mentioned various contracts and, in particular, the signalling contract and I heard the name Siemens, but I couldn’t help hearing that and wondering how many companies there are worldwide who can actually fulfil a contract like that.
John Murphy, URS
Answer
Our contracts are big. The biggest systems contract we have is something called the C610, which is sort of tunnel main works to come and do power and M&E fit out and such like and what we are seeing is that you get big companies and even then going into partnerships. So, on the signalling I think we had nine that we then took through pre-qualification and got five to bid. I won’t say the names, but one dropped out because they just couldn’t fulfill two large contacts they had and another one withdrew so we were left with three on that. With the C660, which is a similar size of contract, we are talking many tens of millions of an initial contact value. That’s for the controls and communications that were going between eight or nine stations, communication systems, radio and fibre networks. Crossrail data networks is a C660 contract, we are down to three.
We had five on that one, but two dropped out and so we’ve got three left. So there are not many and we want a proven product, sort of CBT C signalling product and there are four or five big companies. They’ve all got products and it’s not just the technology, because the technology is out there, it’s having the commercial and the ability to support the contract values and the ultimate guarantees, commercial guarantees, legal guarantees, indemnities and all those sorts of things that Crossrail requires. So it’s more than just the technical capacity. But you generally tend to have big companies who will do that. We have a very robust procurement to make sure we have the right thing and it’s generally biased in terms of, weighted in terms of the right technical and low risk sort of project solution, rather than just the initial headline cost.
Question 8
I had a question on the heat rejection of the train. On the rolling stock you were saying that they have regenerative braking. I would like to know what kind of figures are you expecting from the rolling stock manufacturer. And then the second question was the ripple effect of that on the C610, the M&E or the contract, which is responsible for keeping the stations and the tunnels cool at whatever temperature, 27, 28 or under 30. The interface between the two – what if the first contractor of the rolling stock cannot provide that kind of heat of the regenerative braking so that the heat is reduced?
How have you managed this interfacing between the different contractors, which is very difficult?
Mohammed Tabara, Arup
Answer
I don’t have any figures for what has been calculated and, actually, we don’t yet have a contractor for the rolling stock nor a contractor for the ventilation system. For heat that is generated by the train there are various modes of operation of our tunnel ventilation system. It’s primary role is to do smoke management, but to then manage an excess build-up of heat that could risk the operability of the air conditioning and the comfort of the people on board, we have extract systems in the stations to manage that, as well as shafts at each end of each station. I think what you are illustrating are a huge amount of systems integration in this case it’s not just computer systems handshaking and exchanging timetable information, but it’s doing a sort of physical dynamics. All we have is a very robust interface that covers this kind of interface arrangement and all these issues have already been assessed to a degree by design assumptions and performance constraints and suchlike during the reference designs with our framework design consultants and have gone into the works information and had design engineers looking at that and now we’ve ultimately got to have people delivering against that and making sure that their deliverables comply with those requirements. But I don’t have the particular figures to hand.
Question 9
My wife complains when she gets into St Pancras on the High Speed One that she has to walk a very long way to connect to the other tubes and so on. Would you be putting travellators in and luggage handling, because one of the things that deters people from using the trains if you have luggage, is that it is much easier to take the car because you’ve got luggage handling, but are you doing something about that, because it is a deterrent. And secondly, you’re not using any lithium batteries, are you?
Mike Brooks, Min South
Answer
Travellators are expensive. I know that they were looked at as a link between Stratford International and Stratford existing London Underground exchange and that wasn’t put in and there is a DLR extension to cope with that. There are no travellators in at Crossrail nor are there any excessive transits. There are one or two. I was on one the other day at Green Park or somewhere. There are one or two on the London Underground where you think you need a travellator. In fact I was on one at Waterloo the other evening, but we don’t have any links of that length between Crossrail and London Underground. There are lifts if you are mobility impaired, and if your mobility is impaired because you are lugging luggage then you will use lifts. All that, I trust, by our station designers has been fully taken into account and not like my experience yesterday at Westminster in trying to transit up to the District and Circle line level from the Jubilee, you have to go up to station level and then down so you can do it in lifts but not just in one journey. You have got to change your lifts.
Lithium batteries. I don’t know but it wouldn’t surprise me if rolling stock or such like bidders, their designers of products could consider that.
Obviously I know that in 787s and I like my aeroplanes and I’m getting on one next week. Obviously they are all grounded anyway, but I want to see them up in the air as soon as possible. The latest solutions I see there is they are going to try and get the FAA to let them fly, by containing possible risk of fire and venting the gases to the outside rather than the redesign that would take, perhaps, a year or two. I don’t know about that but I’m sure the contractors have thought about that. I have to think about rolling stock. We have a lot of back-up batteries for things like signalling systems in signalling centres, but there are a lot of good old lead acid kicking around there to do UPS and suchlike. But I do wonder about the trains. I don’t know. You’ve posed a question I don’t know the answer to but I am sure the big names who are bidding on our rolling stock if they are thinking about that will perhaps be backtracking quite quickly.
Question 10
I have always thought that one of the biggest challenges to Crossrail is integrating what is essentially a Metro in the central section with a timetabled railway on either side, particularly as these trains are very large for Metros and are going to handle a huge number of passengers. Also the dwell times and the congestion is going to move from station to station during the day, which is not really easy to predict right now as the system matures. The question is in two parts. How robust is this system to cope with that and has it ever been attempted anywhere else in the world? Are there other examples, similar examples, or are we boldly going where no man has gone before?
Dave Hindle, OTB
Answer
In concept we are not going where people have never gone before, but in terms of the demand that we are looking to do, we are pushing new boundaries there and I think, without doubt, that I tried to do some sort of validation comparison of control and who else has solved this. It is a big challenge. It’s easy for us as I said in the presentation, to move that responsibility on to the suppliers – to say look you can deliver a new signalling system, you can put all the fancy technology and software on there, we will work with you in terms of what’s feasible for a signaller to do, because that’s all new and existing and we can easily accept and change that. Where we’ve got to integrate with both existing Network Rail practices and organisational structures about how many people and how they communicate and operate that and what ability Crossrail have got in the Central Control Centre with the person who is the train running controller top manager, how can he influence that regulation of others and he’s heavily constrained in doing that and you’re only as good as the information you’ve got, so we’re going to put in this big sort of overview display, but that is a passive thing, but in terms of the alarms, that are going to start to tell you and warn you about information, about what levels of things you can deal with automatically so that the Signaller can concentrate on bigger perturbations of the system, can automatically make what’s called sort of adjustments to the automatic timetabling because all the routes have to set automatically – you don’t have a signaller who is going to automatically call routes and the system is going to manage the dwell times or handle the level of swapping trains around maybe bringing one out of Westbourne Park ahead of the train that’s running late off the main line and such like.
There’s a huge amount of work to be done on that side and keeping me busy, so I have every confidence.
Dave Hindle: It’s very ambitious isn’t it?
It is very ambitious, but it’s not overly ambitious.
Dave Hindle: No, I’m just wondering if the system is designed to be robust to cope with these inevitable huge variations we see.
Well the Central Section, there’s two elements of the system. One is that physically, can we move the actual train, do we have the power and do we have the headway that signalling, but then it’s about the decision making and the operator all you have to do is do the wrong thing and then you’ve got a hold up of trains and the whole thing can just fall apart very carefully.
I think the ultimate timetable that is run in terms of where trains go from and to will be dictated to the Central Section so that’s everything going down to Abbey Wood is within our gift to control and regulate and I think the central section will be constrained in exactly how it delivers its service in order to safeguard the interface onto the network.
The other thing is the systems that we have on the network, we’ve got to interface with those and then we said we need all this information for all of these services. You tell us what the predicted delay is when a train is pulling out of a platform in Maidenhead it will be easy to say, but again that would cost money for Network Rail to deliver so, Crossrail has been going in its current actual happening phase for seven or eight years from an engineering standpoint, taking it through Parliament and we’re halfway through the actual engineering and we’re doing the real designs and tackling things that so far have been scripted. This engineer’s going to be employed and challenged. Invite me back in five years time.
