London’s Crossrail project is bringing the world’s oldest underground railway into the 21st Century.
Australia’s three largest cities – Sydney, Melbourne and Brisbane – have all announced plans to build rail tunnels under their central business districts in coming years. They can learn a lot of lessons from London’s Crossrail project, which is approaching completion to get the world’s oldest underground railway fully operational by late 2019.
The £14.8 billion (A$29 billion) project is vast. It starts in Reading in Berkshire around 60 km west of London and will go through to Shenfield in Essex, about 30 km east of London. It will incorporate two spur lines, one the existing fast rail line from Heathrow Airport to Paddington and the other a new line to Abbey Wood around 15 km east of the London CBD on the south side of the River Thames. The total length of the Crossrail lines will be around 118 km and will include 21 km worth of new tunnels.
At 200 m long, the trains will be almost twice as long as current London Underground trains, giving them a capacity of 1500 people per train. This means 10 new stations needed to be built in the city centre and another 30 stations had to be upgraded to accommodate these new trains.
Enabling works began at Canary Wharf Station late in 2008. Tunnelling began at Royal Oak near Paddington Station in May 2012 and was completed three years later.
Making it happen
Head of Technical Information for Crossrail Malcolm Taylor explained that getting the project off the ground wasn’t simply a matter of working out the engineering. There was also a lot of politics.
A Crossrail boring machine prior to digging.“The broad east-west corridor underneath London had actually been established for Crossrail back in the 1990s,” Taylor said.
“I remember working on it a little bit back in 1993-94, which shows you how old the project is. We did a detailed engineering project on a very similar alignment, but it failed then because while the project was quite well engineered, in terms of stakeholder management and managing the politics, it wasn’t anywhere near as robust as the current scheme.”
He said when the current scheme went through Parliament, they put in a lot of effort to showing what the impacts of the project would be and how they would be managed.
“We know what we’re doing around the streets and the disruption that we’ll have,” he said.
“We could persuade London Underground that it’s okay to build a tunnel like that because we know what we’re doing. We have to earn that trust. They didn’t let us do that lightly. We have lots of the instrumentation and monitoring, so that we show that we’re using information sort of sensibly.”
Strength in software
A key to being able to demonstrate all of this was the software they were using, Bentley Rail Track, a Building Information Modelling package which allowed the engineers to design virtually every element of the project.
Taylor said they chose to use BIM at the beginning of the project because of its scale.
Queen Elizabeth II made an appearance at her namesake line.“You have 30 enabling contracts to knock stuff down, 25 contracts hoovering up all of the design consultancies in the UK, and then there were dozens of construction contracts,” he said.
“Creating a common data environment to get everybody to share and use those simple systems is a really neat trick because otherwise, as a client, we could be operating with 100 different organisations with 100 different systems, and in there lies headache and pain.”
Another benefit of going down the BIM path was the British Government’s BIM strategy, mandating its use on all government projects by 2016.
“It meant that we began working in a BIM environment back in 2008-9 before the UK government had this mandating thing,” he said.
“We were very lucky that the same basis that they were after was the one we had already started using. So we had a head start really, about creating that common data environment.”
Steve Cockerell is Bentley’s Industry Marketing Director for rail. He said the CEOs of Crossrail and Bentley decided to establish a Crossrail Information Academy to help inform the contractors on how to use the system properly.
“You can have the best tool in the world, but if everyone is not agreed on the rules and the objectives that are involved, then you’re not going to get great results,” Cockerell said.
“The academy idea was born and has since seen upwards of 2000 people from the Crossrail supply chain move through it, understand why they’re being asked to do things in certain ways, what the endgame is for all this. I think it’s delivered some results.”
Taylor says there are many people who tend to think of BIM as just a 3D modelling tool, but its benefits extend far beyond.
“3D modelling is very important in those early stages for visualising it, turning it around and seeing if it looks right,” he said.
“When we get into operating and maintaining, the models that are critical are things like predicting the failure of an asset. It’s things like, ‘When are you going to do the next piece of grinding on that track?’, because you know when you do the calculations, you’re going to have a potential problem there, therefore you say, ‘I’m going to grind this before that crack takes place.’ That is a model.”
The red line shows the alignment of the tunnels from Canary Wharf back to the city centre.Threading the needle
The London Underground comprises 11 lines, meaning there are a lot of tunnels crisscrossing the ground underneath the city. Add to that building foundations and a range of utility services and there were many obstacles for the Crossrail designers to negotiate when designing the route for their tunnel.
Taylor said they tried to minimise the number of sharp bends or dips which impact both on construction costs (deeper tunnels require longer escalators, etc.) and running costs (the rails on sharp corners wear faster).
“We’re into using head hardened rail and we’re using a lot of devices like greasing the rail, that sort of thing, to minimise rail grinding to stop the cracking,” he said.
“In a perfect world, we would just have a straight line but, with these constraints, it really is trying to get that to work. It is the constraints that really do drive us and force us to put the alignment where it is, plus doing things like going for ramps up to the station and down those connection ways for power.”
He said the biggest challenge came at Tottenham Court Road Station in the centre of the city.
“As you go through the various railway lines, the District and Circle, the Central line, the Northern line, the Docklands light railway, it is progressively getting deeper and deeper and that’s what we’re doing, going deeper and deeper. At Tottenham Court Road, we actually go above the Northern line but we had a very tight gap to squeeze that and squeeze the railway line in,” he said.
“We went 83 cm above that tunnel. This is a 7.2 metre tunnel boring machine just 83 cm above it. If we couldn’t have done that, we would have had to shift the alignment another 10 metres down and that would have cost many hundreds of millions of pounds, let alone, the problem with longer escalators and things like that. It was even tighter there on the other side, more like 30 or 40 cm, but that was only an escalator shaft. And we were doing that with the tunnel boring machine while the trains were still running down here. That was the one that was a bit of a worry.”
A multi-purpose gantry at work in the part of the tunnel running under the River Thames.Lessons for Australia
Taylor said he enjoys travelling on train networks when he visits other countries like Australia and is excited by some of the projects on the drawing board in this country.
“I do like the trains. One of the difficulties that train operators have in this information world is when you have these old legacy systems. Not only do you tend to have old infrastructure, but you have old systems, old patterns of working, old methodologies for people walking the track and looking and checking whether the infrastructure is okay,” he said.
“We talk about sending a drone through with a camera to do a very fast check that our tunnels are okay. You get some asset managers going ‘I’m not sure I’m comfortable with this’. But these drones can go up and look at a shaft. If you see a little spot of water, somebody can go investigate that within say half an hour, as opposed to waiting two days to get some scaffolding in.
“There are so many things we can do now in an asset management world where you need to turn things on its head a little bit. We can learn from a lot of other projects how to do that and how to bring those new asset management techniques into legacy systems.”
One area where Taylor thinks Australia has advantages is in the practice of alliancing contracts involving multiple contractors.
“I know that’s being born out of a combative world, but those types of contract, people working together, is exactly why this information world can be successful, so I think in terms of the recipe, the ingredients are all there. It’s just a question of putting them together and then you can get the people who fund these projects to be able to feel confident that they can deliver on budget and on time,” he said.
“When you can deliver projects on budget and on time and they deliver the economic benefits, it’s sort of a virtuous cycle and they can be relied upon to help stimulate the economy. We have 14,000 people working on Crossrail directly and 76,000 working indirectly, mostly in the UK.”
He said there are a lot of spin-offs and benefits from these projects if you can get them going, but you need a return on investment.
“Crossrail cost £14.8 billion. The return on investment is £42 billion,” he said.
“It’s a good leverage, but you have got to be confident you can deliver those when you say you can and if you think your old processes and your old ways of working have only delivered adequate projects that can be a bit flaky, you do need to think about using new processes and modern technologies to make sure you can nail these.”