3 ms·
London’s tube is particularly bad because of its history running steam trains, of which the residue is still present on walls and ceilings. The Tube is also poo
by bobthepanda 4y ago
London’s tube is particularly bad because of its history running steam trains, of which the residue is still present on walls and ceilings. The Tube is also poorly ventilated due to its age (when this was less considered) and the fact that vent shafts open into places that also have bad air quality.
NYC performs relatively better, it sits close to the surface with frequent vents. There have been simulated bioterror attacks that show the threat in the subway would dissipate quickly due to the ventilation.
The article mentions a bus. I would expect the bus to ventilate more poorly; trains have many doors per car and they simultaneously open for the entire stop in the station, but a double decker only has two doors, the back open to let people off and closed shortly after that’s done, and the top deck has no doors at all.
- TylerE 4y agoI am extremely skeptical of your claims re: London. Steam hasn't operated on the Underground in 115 years, and only ever on a small minority of lines.
- Miraste 4y agoI doubt it's because of steam train residue, but when I was on the Underground it turned all the mucus in my nose black for a day every time I rode it. From searching around, this seems to be a common occurrence for visitors. Air quality there is severely compromised. There's also the health and safety problem of its steadily rising temperatures, about which nothing appears to be being done or even considered.
- bobthepanda 4y agoThey are trying to install cooling at several stations where they deem it possible. The problem is that, generally speaking, Central London lacks spots where you could just punch a ventilation shaft downwards, and the stations are too tight to accommodate modern HVAC otherwise.
- dredmorbius 4y agoI'm not sure there's a significant difference between depths of most of the London and New York subway systems. Most of the London Underground is cut-and-cover tunnels sitting just below ground level (2-6m). The Thames Tunnel is 24m below ground level. The deepest station is Bull & Bush, Hampstead, at 57m (180ft) underground: https://londonist.com/2015/10/how-deep-does-london-go https://londonist.com/2015/10/how-deep-does-london-go https://londonist.com/london/transport/how-deep-is-your-commute-these-diagrams-show-the-depth-of-each-station https://londonist.com/london/transport/how-deep-is-your-comm... The NYC subway also uses extensive cut-and-cover routes, though deeper bores exist. The deepest station, at 191st St. (LRI) is 180 ft. (54m) below ground. About the same as the London Underground. https://untappedcities.com/2013/06/26/deepest-highest-subway-stations-nyc/ https://untappedcities.com/2013/06/26/deepest-highest-subway... https://www.nycsubway.org/wiki/Chapter_14:_Engineering_Features_of_the_New_York_Subway https://www.nycsubway.org/wiki/Chapter_14:_Engineering_Featu...
- bobthepanda 4y agoThere's also difference in ventilation design. A lot of the tube relies on the piston effect for ventilation. NYC's subways are underneath major roads and nearly always features extensive sidewalk venting for the entire length, as depicted in the iconic photo of Marilyn Monroe. https://img.atlasobscura.com/EEahxLmWgG-xahr-cXyJ1_TFUKch_pn0COzG6RZMyXM/rt:fit/w:1200/q:81/sm:1/scp:1/ar:1/aHR0cHM6Ly9hdGxh/cy1kZXYuczMuYW1h/em9uYXdzLmNvbS91/cGxvYWRzL3BsYWNl/X2ltYWdlcy8xMDBk/OGYxYjQ4N2Q4ZjY3/ZTdfMTQ1NTE4MzIy/MDRfNzdkOGI5ZjI1/Nl9vLmpwZw.jpg https://img.atlasobscura.com/EEahxLmWgG-xahr-cXyJ1_TFUKch_pn...
- dredmorbius 4y agoWhere "piston effect" is the passage of trains through the tunnels forcing out air (ahead) and drawing it in (behind), correct? AFAIU that's a major component of any subway's ventillation.
- bobthepanda 4y agoYes. The difference is that London relies solely on the piston effect. NYC has the subway vent grates on nearly every block where a subway runs. Modern systems generally also use HVAC.