7 ms·

And I don't really understand the point of talking about scaling airports when the issue was about scaling the number of airplanes that can move between places,

by Hamuko 7y ago

And I don't really understand the point of talking about scaling airports when the issue was about scaling the number of airplanes that can move between places, since that's an universal problem with it comes to any method of transportation. If you want to move more buses, you need more bus terminals. If you want to move more planes, you need more airports. If you need to move more trains, you need more train stations. The point about scaling air traffic and scaling trains is that you need far less infrastructure to get a plane from place to place. You don't actually even need a huge, expensive airport to do so, since there are much smaller ones and even just tiny airstrips. And unlike trains, once they leave, they have pretty much unlimited room. How many tracks would a train station need in order to accomodate the same number of passengers leaving from Heathrow?

eesmith 7y ago
The point is that most people don't want to simply go to some arbitrary small airport or tiny airstrip. Again, thu2111's statement was: > "Adding capacity to the sky is easy because it's empty. It's essentially just about scaling air traffic control systems." ATC systems are not the only relevant part of infrastructure - airports are also important. You write "you need far less infrastructure". Sure. But airports are also needed for scaling, even if small/tiny airstrips are included, and my point was that airports were omitted from the infrastructure cost. You write "since there are much smaller ones ... tiny airstrips". That doesn't solve London's capacity problem, which is why a capacity question must include the cost of airports. You ask "How many tracks would a train station need in order to accomodate the same number of passengers leaving from Heathrow?" Heathrow has about 80 million passengers per year says https://en.wikipedia.org/wiki/Heathrow_Airport https://en.wikipedia.org/wiki/Heathrow_Airport . London Waterloo has about 94 million passengers per year says https://dataportal.orr.gov.uk/media/1668/estimates-of-station-usage-2018-19-key-facts.pdf https://dataportal.orr.gov.uk/media/1668/estimates-of-statio... , with 24 platforms says https://en.wikipedia.org/wiki/London_Waterloo_station https://en.wikipedia.org/wiki/London_Waterloo_station . Looking at the aerial photo confirms there are 24 platforms, and it appears from Google Maps' satellite view that they are served by 7 rail lines, splitting into 24 platforms. So, 7 tracks are enough to accommodate the same number of passengers leaving from Heathrow. However, that answer doesn't make a whit of difference to my point, which is that if ATC is important cost facto to bring up when discussion air transit capacity, then airports are also an important cost factor.
- thu2111 7y ago
  Heathrow is a rare case. Very few airports max out for such long periods whereas being at capacity is pretty journal for rail lines. That's why the argument for HS2 is capacity oriented.
  - eesmith 7y ago
    My point though is that the capacity of the sky is rather irrelevant since most people are interested in the capacity across the entire trip, not just the air part. All of the biggest airports have had extensive and expensive work done to increase capacity. SFO is about 90% of capacity, if I read https://www.faa.gov/airports/planning_capacity/profiles/media/SFO-Airport-Capacity-Profile-2014.pdf https://www.faa.gov/airports/planning_capacity/profiles/medi... right. And it's worse if the weather is bad. That's why I argue that you cannot ignore airport capacity in your estimates. We can look at the inter-war period to see how capacity calculations had to consider more than just the sky. Pan-Am famously ran flying boats in their transoceanic lines. "Their advantage lay in using water instead of expensive land-based runways, making them the basis for international airlines in the interwar period." (Quoting https://en.wikipedia.org/wiki/Flying_boat https://en.wikipedia.org/wiki/Flying_boat ). Indeed, floatplanes are still important in bush flying for the same reason. I don't know what "pretty journal" means. None of the dictionary definitions seem to make sense. I know the rail lines serving my city are not anywhere near capacity. The train between Santa Fe (my former home city) and ABQ is also nowhere near capacity (see https://en.wikipedia.org/wiki/New_Mexico_Rail_Runner_Express https://en.wikipedia.org/wiki/New_Mexico_Rail_Runner_Express ). A couple of years ago I took the train from San Diego to ABQ. It was also not at capacity.
    - thu2111 7y ago
      Sorry, "pretty journal" was just a bad autocorrect I didn't spot. It was meant to say "pretty normal". The problem with rail is the capacity issues affect the entire line. If one station has busy platforms and the rest are all quiet, you can't put additional trains on that line (unless it's a terminal station and there's a turning circle before that station and you are willing to run trains that don't go there). Also if one line shares fast and slow trains, that kills capacity. One airport can share fast and slow planes, and capacity problems at one airport don't affect other airports. I guess I'm writing mostly from the British perspective. My comment about fuel taxes paying for the roads is (or was) true for the UK. Since privatisation at the start of the 1990s decades of decline in ridership turned around and now more people use the railways than ever. In the UK there are lines everywhere that are not only at capacity but drastically over-capacity, e.g. there's a train departing from Euston on a Friday night that carries more than 2x the number of people it was designed for. Despite that Crossrail - one of the biggest civil engineering projects in Europe - isn't even open yet, the country just committed to an even more eyewateringly expensive new rail line that won't be open for over a decade. Primarily justified on capacity grounds. Heathrow expansion is also very expensive of course. But there's really only one airport in the entire country that has such severe capacity issues, and the expansion is difficult primarily because it's surrounded on all sides by urban development like motorways and villages that have to be demolished and relocated. In the case of the motorway, it's also carrying such large capacity that it can't actually be closed for extended periods, so it has to be moved whilst "live". I think the USA has a different set of issues because the railways are used mostly for cargo rather than passengers. The large distances involved means air travel is the only feasible mode of transport for many routes, and Americans take internal flights all the time whereas for most Brits I know, internal travel is almost always car or train. Business people take internal flights, and even then only quite rarely. I've traveled Acela and indeed it also wasn't heavily used.

by Hamuko 7y ago

eesmith 7y ago

The point is that most people don't want to simply go to some arbitrary small airport or tiny airstrip. Again, thu2111's statement was: > "Adding capacity to the sky is easy because it's empty. It's essentially just about scaling air traffic control systems." ATC systems are not the only relevant part of infrastructure - airports are also important. You write "you need far less infrastructure". Sure. But airports are also needed for scaling, even if small/tiny airstrips are included, and my point was that airports were omitted from the infrastructure cost. You write "since there are much smaller ones ... tiny airstrips". That doesn't solve London's capacity problem, which is why a capacity question must include the cost of airports. You ask "How many tracks would a train station need in order to accomodate the same number of passengers leaving from Heathrow?" Heathrow has about 80 million passengers per year says https://en.wikipedia.org/wiki/Heathrow_Airport https://en.wikipedia.org/wiki/Heathrow_Airport . London Waterloo has about 94 million passengers per year says https://dataportal.orr.gov.uk/media/1668/estimates-of-station-usage-2018-19-key-facts.pdf https://dataportal.orr.gov.uk/media/1668/estimates-of-statio... , with 24 platforms says https://en.wikipedia.org/wiki/London_Waterloo_station https://en.wikipedia.org/wiki/London_Waterloo_station . Looking at the aerial photo confirms there are 24 platforms, and it appears from Google Maps' satellite view that they are served by 7 rail lines, splitting into 24 platforms. So, 7 tracks are enough to accommodate the same number of passengers leaving from Heathrow. However, that answer doesn't make a whit of difference to my point, which is that if ATC is important cost facto to bring up when discussion air transit capacity, then airports are also an important cost factor.

thu2111 7y ago
Heathrow is a rare case. Very few airports max out for such long periods whereas being at capacity is pretty journal for rail lines. That's why the argument for HS2 is capacity oriented.
- eesmith 7y ago
  My point though is that the capacity of the sky is rather irrelevant since most people are interested in the capacity across the entire trip, not just the air part. All of the biggest airports have had extensive and expensive work done to increase capacity. SFO is about 90% of capacity, if I read https://www.faa.gov/airports/planning_capacity/profiles/media/SFO-Airport-Capacity-Profile-2014.pdf https://www.faa.gov/airports/planning_capacity/profiles/medi... right. And it's worse if the weather is bad. That's why I argue that you cannot ignore airport capacity in your estimates. We can look at the inter-war period to see how capacity calculations had to consider more than just the sky. Pan-Am famously ran flying boats in their transoceanic lines. "Their advantage lay in using water instead of expensive land-based runways, making them the basis for international airlines in the interwar period." (Quoting https://en.wikipedia.org/wiki/Flying_boat https://en.wikipedia.org/wiki/Flying_boat ). Indeed, floatplanes are still important in bush flying for the same reason. I don't know what "pretty journal" means. None of the dictionary definitions seem to make sense. I know the rail lines serving my city are not anywhere near capacity. The train between Santa Fe (my former home city) and ABQ is also nowhere near capacity (see https://en.wikipedia.org/wiki/New_Mexico_Rail_Runner_Express https://en.wikipedia.org/wiki/New_Mexico_Rail_Runner_Express ). A couple of years ago I took the train from San Diego to ABQ. It was also not at capacity.
  - thu2111 7y ago
    Sorry, "pretty journal" was just a bad autocorrect I didn't spot. It was meant to say "pretty normal". The problem with rail is the capacity issues affect the entire line. If one station has busy platforms and the rest are all quiet, you can't put additional trains on that line (unless it's a terminal station and there's a turning circle before that station and you are willing to run trains that don't go there). Also if one line shares fast and slow trains, that kills capacity. One airport can share fast and slow planes, and capacity problems at one airport don't affect other airports. I guess I'm writing mostly from the British perspective. My comment about fuel taxes paying for the roads is (or was) true for the UK. Since privatisation at the start of the 1990s decades of decline in ridership turned around and now more people use the railways than ever. In the UK there are lines everywhere that are not only at capacity but drastically over-capacity, e.g. there's a train departing from Euston on a Friday night that carries more than 2x the number of people it was designed for. Despite that Crossrail - one of the biggest civil engineering projects in Europe - isn't even open yet, the country just committed to an even more eyewateringly expensive new rail line that won't be open for over a decade. Primarily justified on capacity grounds. Heathrow expansion is also very expensive of course. But there's really only one airport in the entire country that has such severe capacity issues, and the expansion is difficult primarily because it's surrounded on all sides by urban development like motorways and villages that have to be demolished and relocated. In the case of the motorway, it's also carrying such large capacity that it can't actually be closed for extended periods, so it has to be moved whilst "live". I think the USA has a different set of issues because the railways are used mostly for cargo rather than passengers. The large distances involved means air travel is the only feasible mode of transport for many routes, and Americans take internal flights all the time whereas for most Brits I know, internal travel is almost always car or train. Business people take internal flights, and even then only quite rarely. I've traveled Acela and indeed it also wasn't heavily used.