How fast is your commute?

“A nightmare of a system”

The London Underground has one distinct feature keeping speeds in check.

It is a characteristic that Gareth Dennis, a track design engineer who has worked on projects across the UK, is very familiar with.

“There are tight curves everywhere,” he says. “It’s a nightmare of a system, nothing’s straight.”

The capital’s Tube routes were generally constructed to mirror the paths of the roads above them, therefore avoiding existing buildings.

The result? Where there is a sudden bend in the road, the train line below veers just as sharply.

And whether you are driving a train, truck or tricycle, it is not possible to maintain straight-line speed during a drastic turn.

Dennis adds: “If you have got railway lines that are following either below or above [roads], the curvature has to be very tight because roads have very tight bends, particularly in grid pattern where you are doing a 90-degree turn.”

There are instances across the city where a direct train route would be ideal, but centuries of history force a more tortuous journey.

The Central line changes path almost at a right-angle near Bank for an apt reason – to avoid the vaults of the Bank of England.

Elsewhere, the Bakerloo line takes a major swerve in the city centre so that it mirrors Regent Street.

Of course, there are straight sections. The northern end of the Jubilee line and Tubes coming out of Marylebone benefit from running alongside heavy rail routes. Curves, though, dominate the capital.

Certain Tube lines, such as the Circle, District, Hammersmith and City, and Metropolitan, follow roads the most religiously.

These lines are sub-surface networks built predominantly using the ‘cut-and-cover’ technique, which involves excavating to a shallow depth and covering the top of the newly-made trench with concrete, thus creating a tunnel.

While the relatively low depth of this strategy makes it an economically appealing option, its proximity to the surface inevitably creates high disruption during construction. Excavating under roads, rather than buildings, allowed the London Underground to minimise disturbance as much as possible.

Although some houses were knocked down to make space for the sub-surface routes, particularly on the Metropolitan line, planners generally stayed loyal to the tarmac above.

Dennis explains: “Unless they were bulldozing houses, the curvature was limited by what there was on the road.

“In some cases, if you look at the sub-surface line, you’ll see that the curves are very tight because they are following that road.”

The ‘Deep Tube’ lines - the Bakerloo, Central, Jubilee, Northern, Piccadilly, Victoria and Waterloo & City - are much further below the ground and are less restrained. Some even go below the River Thames.

Innovative engineering can mitigate the hindrance curves have on speed, for example by tilting tracks inwards slightly to reduce the radius of the turn.

However, there is only so much planners and builders can do to raise the pace without reducing comfort and safety.

“We are limited by the laws of physics,” Dennis says. “In the last 40 years, we have got better at curving and better at designing trains to curve more smoothly, but that doesn’t really affect speeds.

“It’s the laws of physics and the level of comfort passengers experience that limits how fast you can go through a curve.”

“We don't use rail enough”

Trains are already pivotal to life in all corners of London, but they are poised to surge in importance.

With population rising and the climate emergency worsening, maximising the railways is essential to the city’s future.

Kendler, who also works with Young Rail Professionals to promote sustainable transport, believes: “Rail is all fundamentally designed around the interface between the steel wheel and steel rail.

 “The beauty of that interface is that you do not need much energy to get something moving.

“If you want to move lots of things and people very quickly and efficiently, rail is brilliant.

 “We don't use that enough in this country.”

 For Kendler, the UK’s reliance on cars consumes unnecessary energy and space.

“Road is not as efficient as rail. We really need to think about how we can increase our capacity for more people and things to travel by rail rather than road.

“Rail is there to take on that [sustainability] challenge and it's an absolute necessity if we want to maintain our quality of life and a habitable planet.”

Such initiatives would be welcomed by train travellers, who can be assured of faster journey times if the government and public support a move towards the tracks.

The imminent opening of Crossrail (also known as the Elizabeth line), which connects Reading and Essex via central London, offers a glimpse into a rail-dominated future.

“Crossrail will be such a huge boost to London, because a journey that could have been three changes becomes just two, one or none,” says Kendler.

“A lot of the time in urban areas, where you are changing trains or transport modes, connections are where you waste time.”

 It is not enough on its own. Kendler is an advocate for more ‘cross-radial’ train services that connect the west and east of London, adding that an improved journey from Wembley to Ealing is his own niche holy grail.

 “London is brilliant if you want to go from the outside of London to the centre of London. If you want to get across London, though, it’s really hard,” he adds.

Other proposals, such as Crossrail 2 and the Bakerloo Line extension, could increase interconnectedness and speed. On a national scale, the High Speed 2 line should ease the pressure on London’s packed stations.

 Yet, for all the irritating delays, manic connections and those pesky Bank of England vaults, Londoners have struck gold with the transport system, Dennis believes.

"What I’d say to anyone that's moaning about a two-minute delay on the Underground is for them to come up to Birchwood Station near the centre of Manchester, and they get a train every two hours if they are lucky.

"It’s an urban area. It’s got industrial, commercial, retail and a large residential area, and they get a train, at peak time, every two hours.

"London has a very, very good public transport system. People who moan about the Underground do not know how good they have it compared to the rest of the UK.”

Quiz: How is your train knowledge?