The London Underground is hell. It can be extremely overcrowded. Some lines are literally dug through clay, which makes them unbearably hot. Gusts of potentially harmful metal dust swirl around, trying to lodge themselves in our lungs.
And then, of course, there is the noise: the trains’ screeching, the wheels’ grinding, the rails’ vibrating, all contributes to the high-volume cacophony that forces commuters to wear their noise-cancelling headphones without listening to anything, just as if they were hearing protections. Travelling on certain segment of the network, one study found last year, can expose passengers to music concert-level noise.
If you are unlucky enough to commute on the Tube every day, you might have noticed that the noise conundrum has been worsening over recent months. It got so bad that train drivers requested that Transport for London (TfL) equip them with some protection. According to Keith Richmond, a representative of train drivers union ASLEF, now every driver travelling on the noisiest lines – Bakerloo, Central, Jubilee, Northern, Piccadilly and Victoria – can ask to be given “can-type ear defenders.”
Richmond blames the increase in noisiness on the installation of new rail fastenings, the Pandrol Vanguard. These fastenings, according to a TfL spokesperson, were supposed to “help reduce noise levels in surrounding homes.” People living above Underground tracks had long been complaining that the passage of trains caused vibrations and noise to be felt right inside their homes. The new fastenings reduced above-ground vibrations, but had the side effect of redirecting the noise inside the trains, where it currently finds its way to passengers’ eardrums.
Some additional factors make things even more miserable than they would be in normal circumstances. According to Luis Gomez-Agustina, who teaches an acoustic course at London Southbank University, “the fact that most of the [London] Underground stations’ surface materials are acoustically hard – [they are] highly reflective, they do not absorb sound – facilitates the noise generated to stay within the space for longer, creating a perception of loudness higher than it would be objectively measured.” Specific tracts of the Tube where rails are particularly worn off, or where trains travel at higher speeds, are usually even noisier.
The question on everyone’s mind – or, at least, on the mind of everyone commuting on the Tube – is whether the noise can cause lasting damage to one’s hearing?
TfL says it cannot. Although the organisation does not have a policy regarding what is the maximum noise level Tube passengers should be allowed to endure, it enforces certain noise limits for its employees, as per the Control of Noise at Work Regulations 2005. Although the regulations explicitly states they are not applicable to “members of the public exposed to noise from their non-work activities, or making an informed choice to go to noisy places”, TfL says that its parameters are a good guidance regarding acceptable noise levels.
The law, which implemented a European directive passed in 2003, sets various limits on exposure to noise in the workplace. A daily or weekly average exposure of 80 decibels requires that hearing protection be available on request, even if it is not compulsory.
Above 85 decibels, employers are required to provide ear defenders and undertake engineering work to reduce the noise; an average noise level of 87 decibels is never permissible. There are also limits on the maximum one-off noise levels – called “peak sound pressure” – workers are allowed to experience, with employers required to take countermeasures at a peak level of 137 decibels, while the impermissibility threshold is set at 140 decibels.
According to TfL, the loudest noise burst on the entire Underground network was recorded on the Northern Line, between West Finchley and Finchley Central, when noise hit 117 decibels for 50 milliseconds. That, TfL said, is well under the noise guidelines’ threshold for peak noise levels. The average loudness for that segment was also safe, at 72.5 decibels.
Gomez-Augustina says that, according to some preliminary research he carried out, it is unlikely that the noise experienced on the Tube can cause hearing damage. “Noise levels, to be dangerous to hearing, need to be a combination of very high – say over 80 dbA [decibels as perceived by the human ear] – and for long time (over eight hours daily ) and this situation need to happen regularly for a long time (say every day for many months) to cause perceivable permanent hearing damage,” he says. “Instantaneous damage to hearing requires noise levels only experienced in very loud explosions.”
Not everyone agrees. In April, EAVE, a company focused on the prevention of hearing loss – which also produces ear defenders – created a noise map of the London Underground, using its own noise monitors while travelling across every line over one day. They found that the average noise level on some lines regularly exceeded 80 decibels, and at times shot well past 90 decibels. While passengers are unlikely to spend eight hours – the equivalent of a workday, as per the 2005 law – on a Tube journey, EAVE CEO David Greenberg still thinks that TfL should be more proactive in addressing the matter.
“At the very minimum, there should be signage – there should be signs to warn people that they’re entering a very loud area, and that they should wear hearing protection,” he says. “A lot of people have tinnitus – a ringing in the ears that can be triggered by loud noise. If you get on the Tube, and you don’t know that you’re about to get, you know, 100 decibels of screaming noise in your ears, that’s very bad for a person with sensitive hearing.”
Joseph Sollini, a researcher at the University College of London Ear Institute, also questions whether the noise thresholds enforced on the Underground should be revised to impose tougher limits.
“The [current guidelines] are designed to only factor in the hours within which you are at work. But we know that you don’t turn your hearing off the minute that you leave work, you hear all day, and you hear all night. And so all the sounds that occurs during your 24 hour period contributes to the potential risk of hearing loss,” he says. “For this reason there are other guidelines that have actually made for people just going about their daily business.”
For instance, he says that the World Health Organisation recommends lower limits. (TfL says that those guidelines are more relevant for people in their homes than for passengers.)
Sollini also says the health consequences of the sudden explosions of loudness experienced on some sections of the Tube are not fully understood. “There’s not enough research done around the risk of those kinds of sounds, and quite a lot of the regulation at present is just based around average sound levels,” he says. “So there’s a potential risk just from being on the tube for short sections where it’s extremely loud.”
The question, for London commuters is: what can be done to stop the noise? A lot of maintenance and engineering work seems to be the answer. According to LSBU’s Gomez-Agustina solutions include “reducing speed of trains, smoothing out or grinding the contact surfaces between wheels and track, rail lubrication, rail improvement or replacement, improving vibration isolation from wheel and track to the carriage, providing air conditioning to seal carriage windows, improving sound insulation of windows carriage walls, damping vibration of radiating panels of the carriage, and even installing active noise cancelling to eliminate loud difficult to remove squeals or hums.”
TfL says it has paused the roll-out of the new Pandrol fastenings, and started “installing noise-dampening pads and carrying out a more focussed programme of rail grinding [to reduce rail roughness, which causes screeching] on the affected track.” In the meantime, buy some earplugs.
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