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The surrounding earth acts as a temperature storage buffer, so without ventilation, it will be extremely difficult to remove heat. Instead of the more difficul
by em3rgent0rdr 9y ago
The surrounding earth acts as a temperature storage buffer, so without ventilation, it will be extremely difficult to remove heat. Instead of the more difficult problem of trying to remove heat, I would rather focus on simply reducing the total heat produced in the lower levels. That can be done by having the lower trains be only for express, so they aren't accelerating and decelerating as much (which is when the heat is produced), with fewer trains in general, and then save the tracks closer to the surface focus for the more heat-producing non-express trains and for the more frequent trains.
On a related subject, the temperature of any cave will remain almost constant at the location's average annual surface temperature. So another option would be to focus on not producing so much heat in the entire city in the first place, to lower the average temperature.
- vertex-four 9y ago> That can be done by having the lower trains be only for express You have no idea of the layout of the Underground, obviously. They're not lower trains that follow the same routes - they're entirely different (and very important!) routes which just happen to be a lot lower than some others.
- pjc50 9y agoIndeed - and the same line varies in depth across the city. Generally lines are deeper closer to the core, and the Northern Line is anomalously deep due to being built in 1860 when soil physics was not so well understood so extra margin had to be allowed for the river. Also, there isn't really such a thing as an "express" on the underground.
- em3rgent0rdr 9y agoThanks, yes apparently I don't have any understanding of London's underground. I was thinking more generally.