Peak performance

Following an epic construction project, the Gotthard Base Tunnel went into full service in December 2016. Forming a super-efficient rail route under the Swiss Alps, it is the longest tunnel ever built for passengers and freight, and has reduced journey times between Zürich and Milan by half an hour. Matt Packer delves into some of the dizzying numbers behind this project.

Chipping away: the project’s beginnings

• 1947: the first concept for the tunnel is sketched and proposed
• 1992: the Swiss government holds a referendum on the project
• 64% vote in favour of the tunnel's construction
• 11 years between government approval and the dig's final breakthrough in 2010
• 6 years between the breakthrough and completion

A rock and a hard place: engineering challenges

• 2,400 workers during peak periods
• 73 types of rock removed during the dig
• 46°C temperature of some rock types
• 28.2 million tonnes of rock excavated during construction - most was returned to the tunnel as processed concrete
• 410m: length of the project's purpose-built tunnelling machine, described as a 'rolling factory'
• 2,300m: depth of the tunnel at its deepest point
• 0.00014%: maximum deviation from intended angles and measurements allowed by project managers
• 250km/h: maximum speed of passenger trains
• Final cost: $12.5bn, equivalent to the GDP of Nicaragua
• 17 mins: total journey time through the tunnel

World beater: top three longest tunnels on the planet

1. 57km: Gotthard Base Tunnel
2. 53.85km: Seikan Tunnel (Japan)
3. 50.5km: Channel Tunnel (UK to France)

But how long will Gotthard's record stand?

Future contender: Bohai Strait Tunnel (China)
Estimated length: 123km
Projected cost: $42.4bn

On the rails: fixtures and fittings

• 2,600km of fibre-optic cable
• 3,200km of copper cable
• 7,200 lights
• 1,900 electrical cabinets
• Safety exits every 325m

Digging for efficiency: vital gains

• 1 million freight trucks will be removed from local roads per year, to be replaced by the tunnel's trains
• 40 mins time saved travelling between Lucerne and Milan
• 67% projected increase in daily passenger numbers by 2025 (15,000 per day expected - 6,000 more than the older Gotthard rail route)
• 25% projected increase in total daily freight by 2020 (from 1,600 tonnes to 2,000 tonnes)
• 325: number of trains that authorities want to traverse the tunnel each day (260 freight trains, 65 passenger trains)

Nuts and bolts: the figures behind Gotthard's 'slab track'

• 131,000m³ of concrete
• 308km of track
• 380,000 sleepers
• 43,800 hours of non-stop work

Blockbuster builds
Three more vast construction projects in the transport arena

Yavuz Sultan Selim Bridge, Turkey
Cost: $3bn
Duration: 27 months
Opened in 2016, this suspension bridge – also known as the Third Bosphorus Crossing – is the world’s widest, at 59m. With a span of 1,408m and a dual-lane rail system, it is also the longest suspension bridge ever to include an integrated railway. Its 322m main tower dwarfs that of any other bridge of its type. Comprising eight highway lanes, the bridge was designed primarily to ease severe traffic congestion in Istanbul. Car trips over the Bosphorus strait now take 15 minutes, reduced from one hour.

Panama Canal expansion project
Cost: $5.5bn
Duration: Nine years
This ambitious build was approved when officials saw that the Panama Canal in its original form could no longer handle growing numbers of increasingly large cargo ships. No wonder – the shortcut between the Atlantic and Pacific oceans originally opened in 1914. A massive and radical excavation made way for a new set of locks – some of which weigh 4,200 tonnes – supported by infrastructure that soaked up 4,400,000m3 of concrete. At the June 2016 opening of the canal’s new section, a giant Cosco ship carrying 9,000 containers passed through.

Second Avenue subway, US
Cost: $4.45bn
Duration: Ongoing
Under discussion for around a century before work commenced, New York’s Second Avenue subway will run over 13.7km along the city’s East Side, providing commuters a relief from jam-packed trains. It is the first major expansion of New York’s subway system for 50 years. Work began in 2007.