My Subterranean Tour of London’s Crossrail
Written by Mark Peplow
It’s a damp, freezing cold day in January, and I’m at the bottom of a massive hole in the ground. This is one of a pair of 41-meter-deep shafts in a part of east London called the Limmo peninsula, a spit of land on the banks of the River Thames. From a drone’s-eye view, it looks as though a giant hole punch has taken two neat circles out of the silty earth.
Back in late 2012, two enormous tunnel-boring machines were lowered into these shafts. Workers fired up the 1,000-metric-ton behemoths (named Elizabeth and Victoria), and their rotating cutting heads slowly gouged their way westwards. When they finally reached Central London in May 2015, it marked the completion of the tunneling work on Crossrail, a new underground railway system that spans London.
Crossrail will be fully operation by the end of 2019, with an expected 200 million passengers carried through its arteries every year. For now, it is Europe’s biggest construction project, with a budget of £14.8 billion (about US $21 billion).
This is my second visit to Crossrail. A few months earlier I strolled around the network’s immaculate new Canary Wharf station, where I learned about the innovations that are helping to bring this railway to life—including wireless sensors and lasers that monitor construction, smart components that warn of their impending failure, and a 3-D virtual model of the whole network that can be explored from an iPad. [For more on all that, see my article, “London’s Crossrail Is a $22 Billion Test of Virtual Modeling.”]
Here at the Limmo site, though, you can see the blunt end of this construction project. The area is packed with cranes, concrete mixers, and dumpsters. Warning alarms rip through the air as heavy loads are hoisted around. The workers wear scarves and balaclavas above their bright orange coats to ward off the cold.
My hosts and I descend the shaft using cramped stairs built from scaffolding and boards. Halfway down is a bizarre sight: a small shrine bolted to the wall, containing a figure of Saint Barbara, the patron saint of mineworkers and tunnelers. Dozens of these statues were blessed by priests and placed at the mouths of Crossrail’s tunnels before work began.
“It’s a tradition, hundreds of years old,” explains site manager Peter Kelly.
At the bottom, we walk along the eastbound tunnel as it curves upwards at a slight incline. Automated lighting brightens and dims as we pass, while bangs and crashes from the shaft echo around us. Rails laid out on the floor are ready to be welded together and mounted on ties by a mobile gantry, a vehicle that looks like a huge robotic spider on wheels. The gantry is currently less than 1 km to the east of here, and closing fast. Kelly says they’re now racing to finish all the civil engineering work at the site by the end of March. And in a few years’ time, trains will come barreling through here at about 65 kilometers per hour, tilting gently as they round the bend.
As we return to the surface, I notice that the short section of tunnel between the two shafts is strewn with rubble. Workmen are loading the hunks of concrete into wheelbarrows, their breath clouding the air from the exertion.
There’s no doubt that Crossrail is a high-tech railway—but building it still involves a whole lot of mud, concrete, shovels, and sweat.
Read more at spectrum.ieee.org