This article was originally published on April 5, 2022.
It starts of with a calm buzzing from the electric wiring as the train depart from the station. Then it slowly builds up to a hissing sound of metal screeching that just gets more and more unbearable…
For a subway system that is likely the quietest in the world, the Toei Oedo line sticks out like a sore thumb!
The main reason for the sound is more complicated that you’d think. It is actually due to a number of rather cool factors:
You see, the construction of the Toei Oedo line started relatively late in Tokyo’s subway history (which dates back to 1927) and it opened on December 12, 2000, to get the magical date of 12/12/12 in the Japanese calendar (which is the 12th year of the period corresponding to the reign of Emperor Akihito). This forced the subway tunnels to be constructed below existing subway lines, which lead them to be built deep underground, with stations as deep as 42 meters below ground.
To save cost, the planning team decided to make the tunnels smaller than on conventional subway lines, and consequently smaller train-cars had to be used. In fact, the Oedo line’s train-cars had to be so small that conventional engines would not fit in them. Instead, a new technology at the time was used, Linear Induction. This technology works with magnetic fields created by a linear induction motor inside the train and a third rail under the train with an opposite magnetic field that propels it forward.
Linear induction motors themselves are not that noisy, but a combination of the increase maintenance cost of the train-cars (which decentivizes regular maintenance or upgrades) and the many sharp turns the smaller tunnels require have led it to be perhaps the noisiest train line in Japan.
On top of this, the depth, unique train technology and maintenance costs have made the Toei Oedo line is the most expensive subway line ever built!
Will the Noise Ever get Better?
Modern train-cars can reduce the noise substantially. Many new train-cars’ wheels rotate independently on the left and right side, which reduces any screeching sound substantially. An additional solution that is already used on similar lines in Japan is to lubricate the train tracks.
However, the Toei Oedo crew does not seem keen to introduce lubricant to its already ballooning maintenance costs, and its rolling-stock is relatively new so there are no plans to replace it yet.
So until further notice, all you can do is to pray that you will never be forced to commute on this line…
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