A district line train to Upminster arriving at Tower Hill Station. Image courtesy of Wikipedia
Arriving at an Underground station and seeing the words “severe delays” (usually as a result of a signal failure somewhere on the circle line) most commuters can’t help but feel let down by the world’s first underground railway.
The tube’s apparent inefficiency makes it sometimes hard to remember and appreciate that it relies on a large amount of science – a discipline usually regarded as efficient and logical.
So in an attempt to remind all you frustrated commuters out there that the tube is perhaps sometimes not as bad as you may think, here are two detailed science facts about the London Underground:
Engineering Excellence
No-one can argue that the London Underground tunnels are a remarkable engineering feat. With several of the current tube lines as much as 20 metres underground, eg. the Piccadilly, Central and Bakerloo Lines, the engineering dangers were also very apparant. Thankfully the necessary equipment had recently been developed when construction on the tube tunnels began.
In 1818, Sir Marc Isambard Brunel developed the original tunnelling shield. Effectively a support structure for maintaining the tunnel while it was being excavated, the shield allowed engineers and miners to work without the risk of the tunnel collapsing. It was used when the soil was unstable and helped maintain the structure whilst the tunnel was being lined with a support structure of concrete, cast iron or steel.
This design was then enhanced by Peter W. Barlow for his construction of the Tower Subway under the River Thames in 1870, which enabled miners to dig behind a watertight screen without damaging any properties above ground. Further developments occurred when Barlow joined with James Henry Greathead, enabling them to use their tunnelling experience to construct of the City & South London Railway (now part of the Northern Line) in 1884. This developement of the tunnelling shield has since enabled approximately 250 miles of track to be laid under London and its surrounding areas, serving 270 stations, with a daily weekday ridership of 3.4million passengers.
With the first London underground trains running on steam (the first electric trains were not used until 1890), other considerations were important in the construction of the tunnels. Ventilation shafts were built at various points along the routes to allow the engines to expel the steam and bring fresh air into the tunnels. One such vent is at Leinster Gardens where a concrete façade was constructed to resemble a genuine house frontage – in keeping with the visual aesthetics of the well-to-do street.
Can you spot which of these houses is a façade? Image courtesy of Wikipedia
Some further great photos of the structure can be seen here.
Air Pollution
An “urban myth”: http://en.wikipedia.org/wiki/London_Underground_air_pollution exists that suggests that 20minutes on the Tube is equivalent to smoking one cigarette and has even been previously quoted by the BBC and the London Evening Standard.
The myth originated from work done by Dr Ben Croxford, a researcher at University College London who at the request of a journalist carried out an estimate of the weight of particulate matter inhaled when smoking a cigarette. Croxford subsequently calculated that a person would have to spend 20minutes in the most polluted part of the London Underground to breathe in the same amount of matter.
However, the calculation only made a comparison of the weight of matter breathed in and Croxford’s research never intended to suggest that breathing in Underground dust was as harmful as smoking cigarettes. The subsequent interpretations of this data by the media is a classic example of how lying can be easily achieved with statistics and how scientists must be careful that their data does not mean the lay-reader draws an incorrect conclusion.
Dust in the tube tunnels is primarily iron (from the wheel-rail interface), quartz silica (from the train’s brakes), passengers’ clothing fibres and cells from human skin and hair.
These particulates are much less harmful than those found in traffic exhaust which have been found to aggravate asthma. . With concerns about asthma growing worldwide, particularly following the campaigning on Asthma Day 2009 last week, it’s reassuring to know that although the air you’re breathing in when squashed into a packed-tube might smell of body-odour, it’s unlikely to cause you too much harm.
Fascinating post Chloe, thanks.
I got on the Victoria line train at Warren Street yesterday evening; went inside, lots of space. The train didn’t move and the carriage soon filled up. Then came the announcement “The Victoria line is suspended from Victoria southbound, due to a person on the track between Stockwell and Brixton”. Deep sighs, some people got off. We made it to Oxford Circus and then stopped before Green Park (my change for the Jubilee Line). Uh oh, we think.
Then,
“We will now be travelling all the way to Brixton. The person who was on the track is now obviously off the track” at which point the whole carriage laughed.
Brilliant.
Glad you enjoyed it Richard. There’s a wealth of fascinating information on the internet about the tube, but sadly not enough space to blog about it all. If you’re interested, it’s worth looking at the world record of the quickest tube journey around all stations, the now disused stations, the london underground song produced by Dr. Adam Kay and Dr. Suman Biswas and this London Underground blog
That is an interesting post. In New York they temporarily plonked down a plastic orange and white stripey plastic chimney in the middle of 2nd avenue to vent steam from underground. I wish it had been the facade of an elegant period home.
I was also drawn to the facade vent – what a great idea! In Paris they are just grills in the sidewalk, for blowing up one’s skirt (or kilt).
As an asthmatic, I’ve always been convinced of the physically irritating effect of traffic (particularly diesel) fumes. In the metro, it’s not the same effect – but I always am aware of a particular odor in the air of the tubes themselves, not redolent of bodies, but something particular to Paris that hits the back of the sinuses and that one can almost chew (but it’s subtle). You get it coming out of some basements and garages, too, so it’s more to do with the labyrinth of tunnels underlying the city and perhaps its microbiological population.
Oh yes — the Tube certainly has a specific odour. There’s a vent round the corner from my house, and sometimes walking past it I get the rumble of a passing train and that subtle, but distinct smell.
“Engineering Excellance”
…but not spelling excellence, obviously……
The Metro’s odour may come from its rubber tyre technology. The use of rubber traction is an ingenious application of engineering (Tube science v, Metro engineering) but the price that is paid is the loss ov volatiles (platicizers etc.) from the rubber tyres caused by frictional heating. An interesting application of Tube Science is the gravity assisted braking and acceleration used on the Victoria and Jubilee lines. The stations on these later lines are raised about 1m above the track level. So trains entering a station go uphill and slow down. This loss of kinetic energy is stored as potential energy and the train accelerates out of each station by going downhill. A brilliant use of civil engineering to achieve highly efficient regenerative braking.
Nice post, Chloé.
London has plenty of unusual Tube vents when you start looking. Outside Bank station, for example, is a statue of James Greathead, who you mentioned above. If you look at the base, you can see that it contains a ventilation shaft. Nearby in Paternoster Square, another vent is contained inside the column, and another in a sculpture by Thomas Heatherwick. They’re everywhere.
Andy – terribly sorry for the spelling mistake.
I could blame it on the fact that my right hand is currently bandaged up and I’m using my left hand to type, but in actual fact I just didn’t pick it up when I was proof-reading. Many apologies.
In some parts of Waterloo underground station there is a persistent faint smell of vomit. I seem to remember reading somewhere that it is due to some fungal infestation – is that right? Will it ever be eradicated?
Do people think that different lines have different smells? For me the Metropolitan line always feels different – it has a vaguely damp smell, if that makes sense.
Interesting post Chloé – I never knew that about the facades.
Nice one Chloé. I have always been impressed by the sheer scale/coverage of the Tube system, and the number of people it usually moves in any given day. Mind you, I don’t have to ride it every day ;)
Chloé,
I think you should have blamed it on your bandaged right hand. I’d have believed that and said, “Awwwwwww.” :)
I hope your hand gets well soon. And next time it’s probably advisable to pay attention to that sign at the zoo which says, “Please do not feed the lions.”
Take care
Andy.
My family is planning a trip to England next month. This will be our first trip to London and I am pretty excited about it. I heard that the cheapest way to travel around London is to use the tube. But I’ve received to warnings about the Tube:
Warning 1: Do not use it in the summer
Warning 2: It has a bad smell at some parts of it
Is this true?
Justin
Justin -
The tube can be very hot in the summer, it is true. When the weather is hot they advise you to carry water. I don’t bother and have lived to tell the tale.
There are all kinds of smells – some of them mentioned above. None of the smells will kill you.
The thing to remember is that many of the lines are quite old. Probably the cleanest are the newest – the Victoria Line (40 years old) and the Jubilee Line (newest part about 10 years old).