Rabbiting On: If hot air rises, then why is the London Underground so bloody hot?

For years we’ve been taught that hot air rises and cold air sinks.

That’s why attics are hot and caves are cold, right?

Well then tell me this, why is the London Underground so bloody hot?

I can’t be the only one who finds myself dripping with sweat and gagging for a spot next to the window to cool my flushing face.

“Please, please, please tell me it’s not just me”, she says, wiping her SULA.

I know I’m a warm person (some might say hot stuff, and who am I to disagree?) but the Tube is next-level sweltering.

It’s beyond that of tropical islands and closer to the temperature in the depths of hell. Even Hades is breaking a sweat on the Victoria Line.

And that’s just in the winter.

So because I want everyone in the office to know I am normal for arriving a drippy mess, I’ve decided to look into the science of why the Tube is so warm.

Here’s what I found (it offered me little comfort).

Some of the Tube lines, particularly the older ones like the Central and Northern lines, run deep underground. The further you go beneath the surface, the less natural ventilation there is, which can trap heat.

Ok, that makes sense.

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To add insult to injury most of the Tube’s trains do not have air conditioning. The narrow tunnels make it difficult to install effective cooling systems without reducing the space available for passengers.

Hmm, they seem to make it work in Barcelona but alright.

The Underground has been operating since the late 19th century, and over time, heat from train brakes, motors, and passengers has been absorbed into the clay surrounding the tunnels.

This heat builds up and has nowhere to dissipate easily. Great hundreds of years worth of sweat.

See, I told you! THE. DEPTHS. OF. HELL.

Perhaps the most obvious reason, London is a very busy city, and the Tube often operates at or beyond capacity, with trains packed full of passengers.

The body heat of these passengers, combined with the lack of ventilation, further raises the temperature inside the carriages. We’re just stewing in each other’s hot breath.

Of course, some newer lines, like the Elizabeth Line, have modern trains with air conditioning, but for the older parts of the network, the heat remains a challenge.

So my lesson of the day is, don’t try to be chic by wearing a leather jacket on the underground, it’s tank tops and shorts from here on out, baby.