Crossrail’s head office could hardly be in a more auspicious part of London. Located on the 30th floor of 25 Canada Square, in the heart of the Docklands financial district, it shares a building with several high-profile banks and financial companies.
Its location also means that Rhys Vaughan Williams (above), head of mechanical, electrical and public health (MEP) engineering for Crossrail, can point out of his window at the parts of London that will be transformed by the opening of his railway in 2019.
“All of that stretch by the Thames, through Woolwich down to Abbey Wood, will be revitalised,” he says. “There’s a lot of brownfield sites ready for development. The impact will be massive.”
The mammoth new east-west line, which stretches from Shenfield in Essex and Abbey Wood in south-east London through central London to Reading in the west, has already been affecting house prices. After 35 years of planning and development and seven years of construction work, property developers and landlords have realised the £14.8 billion railway is actually happening.
Many fear that the increases in property prices will force many ‘ordinary’ people out of the less salubrious areas of the capital. It’s a problem that Williams is aware of and concerned about, but that is not under his remit as head of MEP. In fairness, he has plenty of other things to worry about. As Crossrail moves out of the civils and construction phase into the fit-out of stations and tunnels, his job becomes progressively harder, culminating in the start of commissioning in January 2018.
“One of my biggest challenges is that we’ve jumped from a civil, structural project to talking about moving trains, without considering the people coming in and out for the next phase of construction,” he says. “Our next milestone is closing out the design, but my personal focus is on changing people’s mindsets on understanding the complexities of the fit-out stage.”
The workforce that is building Crossrail will peak at 9,000 during the next few years, and has changed dramatically as the project has progressed. It has flipped from 80% civil and 20% mechanical and electrical to 20% civil and 80% M&E. Examples of mindset change have to occur all the way through the workforce – from how all those workers move in and out of sites, and how equipment is installed, to the use of new methods and materials. These are things that civil engineers wouldn’t necessarily have considered, but are the minutiae that the project’s MEP engineering department thrives on.
Risks rising
“Traditionally, civil engineering eats into the time allocated for the fit-out, so there are more critical decisions that have to be made quickly. Our risk profile increases, which is where the value of a high-performing team comes into its own,” says Williams. “We have to make big decisions and stand by them, but there will always be issues we didn’t anticipate – such as noise from mechanical systems, and seepage of water in unexpected places.”
The project is spread over 30 construction locations, with eight being classed as ‘major sites’. Some are trickier than others and each station is different, even at different ends of the same platform. But each has had, or will have, its turn as the ‘problem child’ before the project is complete, says an unfazed Williams.
“The problem children rotate around. Liverpool Street had the Bedlam grounds [involving archaeology of 16th- and 17th-century burials] around the station and the restrictions we had around the civils basement [a subterranean basement had to be broken out to enable the works] – it was horrendously complicated shrinking that down. Putting in new infrastructure to run the existing railway, the tunnels were close, plus there was switchover of old kit to new and replacing power systems for the existing infrastructure. This stuff is so fragile.”
A lot of the cables are paper-insulated lead sheaths, so they crack when moved. The switchgear is also sensitive. Another, well-documented civil engineering problem was the reinforcement of foundations of old structures with resin grout to strengthen them, so that Crossrail tunnels and operation don’t disturb them. The large-scale ‘service moves’ – shifting sewers, gas, power and communications infrastructure – are also “massively complicated” in London, says Williams. “We’d discover cables and not know what they are for, as they are not identified on any survey or historic drawings.”
Myths about Crossrail abound. One is that the line is fully air-conditioned. In fact, only the trains will be air-conditioned. The only station to have air-conditioning will be Canary Wharf, as this is by far the largest station and connected to the retail centre. In all other stations, engineers have developed a passive ventilation system to reduce power consumption.
The original specification was for full air-conditioning – the faster trains will dump vast quantities of heat, combined from their braking systems and onboard air-conditioning. At first, extractor fans under the platforms were specified to suck hot air out from under the trains. However, engineers realised that running fans to suck hot air out also removed the cool air, so now just ducts are used. “Extraction had no benefit – it was a hugely expensive luxury,” says Williams. “We realised that we can run it much better with just the movement, not the chilling, of the air.”
The passive cooling systems work by dragging air down the escalators from outside, along the platform and out through the ‘over platform extract’ that was originally designed for smoke removal. This system creates a constant flow of air through the stations and platforms, a sensation akin to a “slight breeze on a hot day”, Williams says, sufficient “to change perception of the environment”.
It’s an elegant solution, and also reduced the number of expensive tunnel ventilation and evacuation shafts needed. Originally the railway was planned with 25 tunnel shafts in different places in London. This number was reduced to five.
The solution is also typical of the efficient approach to design that Crossrail has attempted to adhere to. Instead of engineering for what the maximum has to be, with layers of redundancy for safety on top, Williams says the attitude has been to develop the “best fitting” solution. It seems a simplistic philosophy, but it helps to counteract the over-engineering that can occur with so much complexity and so many partners. “If we don’t need it, we don’t use it,” he says. “The primary focus is safety, but engineers have to be careful not to overcompensate, that we end up with systems that look after systems. We work back from worst-case scenarios.”
This approach relies on the experience of Crossrail’s engineers. Designs and design reviews are looked at from the perspective of the end-user, and from how a room is going to operate. Instead of considering the maximum amount of heat a room will give out – for example, a room containing back-up batteries for emergency lighting – the focus is on what the room is being used for, under what circumstances it will give out the maximum amount of heat, and for how long. “We’re reducing our heat loads by up to 60%. The cooling equipment is reduced, the ductwork is reduced, the pipework is reduced, power consumption is down. It’s all a lot more efficient,” he says.
Another aim is to maximise the use of new technology, says Williams. “Systems have moved on. Escalators used to cost £1 million each and be built especially for the Underground. Now there are more escalators in shopping malls. There is more innovation and technology, and replacement strategies are more slick. Unfortunately, we live in a disposable world, and it’s the same in the construction industry. So we’re trying to drag all these new technologies into the Underground, and we’re using Crossrail to do that.”
Thinking smarter
This process has informed the approach to the installation of IT systems. A SCADA (supervisory control and data acquisition) system is being installed for critical systems and a BMS (building management system) for maintenance, while DALI (digital addressable lighting interface) is being used for the lighting systems.
To get the job done, the MEP armoury includes several new tools. The most significant of these is building information modelling (BIM). Its use underpins the fresh approach that MEP has taken with Crossrail, of thinking smarter and more efficiently. “The BIM is for the whole life of the railway. There is the physical railway and the virtual railway,” says Williams.
BIM has enabled the project to use just-in-time supply chains and to create synergy in the various systems, so engineers can see if there are different make-ups and components in the railway. To avoid technicians having 20 different kinds of circuit breakers or damper motors on their vans, they will refer to the BIM before maintenance. So can Williams imagine building Crossrail without BIM?
“It would have been much harder with sequencing,” he says. “The coordination of services would be more difficult in the confined spaces underground, and we would be relying a lot more on electricians and fitters on-site. We also try and fabricate as much as possible off-site, so the suppliers need to know exact dimensions.”
To aid this accuracy, the project is using point cloud surveys to validate the build. After construction, engineers use a laser system to scan the station. This scan generates a digital cloud of geometrical points that is used to produce another 3D model. That model is then compared to the existing BIM model, to verify the build and adjust it if necessary. Any systems being installed are modified to accept the tolerance changes. The application is new ground for the railway sector.
There are different levels of BIM, but Crossrail’s target is to have a fully maintainable model that lasts the full lifetime of the railway. In the future technicians will be able to access the model via a GIS-controlled (Geographic Information System) tablet or mobile device, effectively creating an ‘augmented reality’ application. The engineer goes to the site, points the device somewhere and the device tells them what lies behind cladding, and where the trunking or switch gear is. “You can take panels off without removing them physically,” says Williams.
“In the utopian BIM world, we will be able to know how long things have been in service. We’ll be able to track usage for predictive maintenance.”
As well as capturing and retaining the BIM data, it is as important to capture the information on and experience of the project from the brains of engineers, he believes. This process will enable learning to be transferred to other big infrastructure projects. So Crossrail has created a legacy learning system which includes a website, and is partnering with engineering institutions, including the IMechE, to publish technical papers.
Just as Crossrail will make an impact on the physical and economic London landscape outside Williams’ window, the project will also leave a legacy for infrastructure engineering. Through its pioneering use of new tools, techniques and, he hopes, knowledge, and engineers ready to apply them, it should change the discipline for the better.
Steep learning curve for graduates
The Crossrail graduate scheme has 15 members spread over two intakes, and is innovative for several reasons. Unlike most schemes, which offer four-year placements, Crossrail’s is done in two.
“It has the steepest learning curve that any of my staff and myself have ever come across,” says Rhys Vaughan Williams, head of mechanical, electrical and public health engineering. “There’s no hanging around offices doing the filing here. On this scheme, they are at the coalface and seriously tested. They have to produce technical papers.”
Research that the graduates conduct on the scheme is linked to real applications for Crossrail, such as the understanding of ratios in cooling systems depending on their application, the use of anti-frost mechanisms, or bi-metallic corrosion. Their day-to-day routine includes working with contractors, dealing with contracts and compensation cases, using the New Engineering Contract system.
“They experience a mix of commercial and problem-solving issues on different sites,” says Williams. The graduates on the scheme are rotated around different functions at Crossrail “to promote an understanding of the project as a whole”.
The scheme is accredited by the IMechE and will account for up to two-thirds of the way towards CEng status. Most of those finishing it will go on to work on Crossrail and Crossrail 2.
“This isn’t short-term – I look at this as a 120-year project. The graduate scheme is one of the add-on advantages. We’re trying to change the indus-try here,” says Williams.
Bigger, faster and more reliable
Crossrail will become the Elizabeth Line when it opens in 2019.
When asked about the project, most people want to know about the tunnel-boring machines and where all the dirt goes, but interest is gradually drifting towards the railway, says Rhys Vaughan Williams, head of mechanical, electrical and public health engineering.
“Everyone assumes we are below everything else in London. But we have to weave in between all the other infrastructure. Explaining how we do that is interesting. It’s a great big jigsaw. Then people want to know about the trains, how fast, how long the platforms are.”
People will be impressed by the enormity of the scheme, he says. The sheer size will be something they haven’t seen anywhere before – the platforms are three times the size of standard Underground platforms.
They’re bigger in global terms, too, he says. “New York, Moscow, Vienna – Crossrail is so much bigger and faster than anywhere else. London will be proud of it and wonder why it didn’t happen long ago.”
Did you know? Building information modelling
Building Information Modelling (BIM) is a digital representation of the physical and functional characteristics of a facility. A BIM is a shared knowledge resource – the information it contains is used to make decisions about design, operation and maintenance throughout the building’s lifetime. The concept of BIM was first proposed in the 1970s, although the term and software did not become commonly used until the early 2000s.