We’ve all been there. You’re on your morning commute, trying to read, scroll, or just zone out… And then comes that unmistakable noise. Wheels grinding, tunnels roaring, and suddenly you’re wincing at the sheer volume echoing off the walls.
Welcome to the Underground, first opened in January 1863, began with the Metropolitan line, operating between Paddington and Farringdon and serving only 6 stops.
Since then, London’s underground labyrinth of tracks and stations has grown to a whopping 272 stops and 402Km of track.
And, if we add in the Elizabeth Line and the DLR, we get to a bigger sum of 312 stations + the additional 156Km from the Elizabeth Line and DLR, taking the sum to a final distance of 558Km of track.
That’s enough track to get you from London to Amsterdam.
But with the scale of the Underground, comes the noise. The London Underground is infamous for it’s incredibly noisy lines across the capital. There were more than 1300 noise complaints made between 2020 and 2022!
So, as part of our Decibel Derby campaign, we took our SV 971A Class 1 Sound Level Meter down into the depths of the Underground to find out: What are the loudest Underground Lines?
But quickly, how are we measuring this. Well, we’re looking for 3 different parameters, the LEQ, the L90 and the LMAX.
The LEQ is simply the average sound level over time, giving us an overview of what line is the noisiest, considering the entire recording.
The L90 is the noise level that was exceeded for 90% of the time, this gives us a good base level for what the consistent loudness was throughout the journey, excluding any sharp bursts of noise.
And the LMAX. This is the loudest period of noise recording throughout the measurement, this will give us a good indication of what the maximum noise level the tube line reaches.
It’s really no surprise that the newest line is the quietest, the Elizabeth line isn’t even 5 years old and is a marvel of modern engineering. The tracks are also the quietest, clocking in at an LEQ of 74.3dB.
12. Hammersmith & City – 74.7dB
11. Metropolitan – 74.8dB
10. DLR – 75.2 dB
9. District – 77.6dB
These lines all sit from 74dB to 77dB. Which isn’t that loud and manages to fall just inside what is classed as non-hazardous nose. This is the equivalent to a hoover or dog barking.
These lines also have more effective noise management infrastructure, For example the District line has double‑deck bridges and open-air tracks which let noise dissipate naturally
8. Circle – 81.4dB
7. Bakerloo – 81.7dB
6. Victoria – 82.2dB
These are all in the range of the low 80s. We’re now entering the danger zone. Long term exposure to noise over this level can cause mild hearing damage.
The Circle line (among others) was built by cutting open the ground and building a tunnel before covering it. This method creates tunnels with a less “tinny” tunnel reverb, offering a quieter perception than deep-level lines.
One thing that the Victoria line does well is that it has ATO (Automatic Train Operation), meaning that it has smoother, more consistent acceleration and braking, reducing harsh noise.
5. Jubilee 84.7dB
4. Piccadilly 85.0dB
3. Central – 85.7dB
These all enter the threshold where long term exposure can cause mild to moderate hearing damage.
One thing you may notice about the Piccadilly line is the constant low hum when on stations like Piccadilly Circus and Leicester Square. This is because of air relief shafts installed in the 70s. While it does reduce the amount of air pollution, it comes with the trade-off of additional noise.
The Central Line is one of the oldest and longest in the network, and it shows. Its tunnels suffer from extended reverberation and lack any modern sound damping.
2. Waterloo and City – 91.7dB
Despite its singular stop, this line hits a crazy 91.7dB which is way into the danger zone now. With long term exposure causing moderate to severe hearing damage.
1. Northern Line – 98.4dB
And the ‘winner’ of the loudest Underground Lines goes to the Northern Line. With a crazy average sound level of 98.4dB. That’s the equivalent of motorcycle revving but the entire time you’re on the line. It even clocked an LMAX of 105.7dB, just a few moments of exposure to that could cause permanent hearing damage.
Well, there’s a few reasons. Reason number 1, the northern line is just… Old. It was opened in 1937 but some parts of the track date back to the late 1800s, older tunnels often used bare brick or concrete with no acoustic treatment.
Reason number 2, it is the deepest line in the whole Underground. This means that the tunnels are more reflective than other lines. It is also extremely windy, which also adds to the already loud track noise.
And the tracks are another reason why it’s so loud, firstly they’re in relatively poor condition, with corrugated tracks in the process of being removed.
Another factor of the tracks is something called Padrol Vanguard. This is a type of fastening, that, ironically, was installed a good few years ago to address residential noise by limiting how vibrations travel. However, it ultimately backfired and resulted in more in-carriage noise.
This isn’t just an acoustics nerd’s curiosity, it’s a real health concern:
For professionals in acoustics, the Tube provides a fascinating (and frustrating) example of:
And of course, we’d be remiss not to mention again that all our measurements were captured with the SV 971A, one of the smallest, and most reliable, Class 1 meters on the market.
This blog is part of our Decibel Derby series, where we take sound level meters across the UK to measure the real noise of everyday places, from stations to airports to the pub.
Got a loud location we should measure? Let us know!
Or check out the full decibel derby here.
Let’s keep listening. Because what you don’t hear (like gradual hearing loss) … still matters.
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