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Comment by mlsu | Hacker News Reader

For a coast to coast flight, at least 30-40% of the flight time is spent getting to the airport earlier to de-risk the TSA line, or standing in the TSA line. Or, going outside to hail a cab to the airport, sitting in airport traffic, and driving to and from the airport.

For a 5h flight from LAX -> JFK, approx 3-5 hours is spent doing these things.

So, to shorten the 8-10h of an LA to NYC trip, the easiest possible thing to do is... build a f%@#$ train.

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I was with you until the last sentence. Your train trip that crosses two continental divides is still going to take you more than a day. Even a "spare no expense" rail project isn't going to make that cross-country trip palatable for most travelers.

It might be palatable if it's quite a bit less expensive, which could be the case if we start passing externalized costs (e.g. offsetting the impacts of carbon emissions, pollution, noise, etc.) down to the consumers who use these services.

I guess GP meant to build a train from downtown NYC to JFK.

Another one? JFK is connected to the subway.

It is a slow subway train that requires transfers at Jamaica to the airtrain and then an internal airport people mover. Some people need multiple transfers from

WTC/Penn/14th street are centrally connected stations that should have a direct connection to JFK.

Run an express A-C-E train from central-park, 34th, 14th, WTC, Atlantic, Jamaica, JFK. It should not be that hard. While we are at it, run an express downtown manhattan to Newark train/BRT too. LaGuardia is....hopeless.

The upstream comment ambiguously suggested a train as a solution to an 8-10 hour door to door LA to NYC travel time. Either that means connecting the airport to the city by rail or the cities themselves. Sub-8-hour LA to NYC by train is beyond any currently known technology. JFK is already connected to NYC’s subway by rail.

> Sub-8-hour LA to NYC by train is beyond any currently known technology.

But oh so close!

https://news.ycombinator.com/item?id=26589001

;)

No, it's connected to AirTrain, which is slow and unpredictable, which is then connected to either the A or the LIRR.

Sorry I meant that you can use rail to get to and from JFK to the parts of New York served by the subway.

If the claim was to build a sub-8-hour LA to NYC train that’s obviously not going to work because of physics. If the claim was we need rail to LAX and JFK that’s silly because both are already served by rail.

> build a f%@#$ train.

Until someone creates an incident on said train, and then suddenly you have to do the TSA dance at train stations too.

Most of Europe doesn't even check if you have a ticket before boarding a train. Some countries check tickets at the station, but I have never been checked for anything else. And there have definitely been incidents.

You get through airport-like screening (metal detectors, baggage scan) when crossing the eurotunnel.

The Eurotunnel is kind of special because it is an especially long undersea tunnel. It is very much the exception, you won’t see that for any other trains in the UK or France, high speed or otherwise.

Honestly, with Pre-Check, I haven't had a security check be a major issue in years and years anyway. I still tend to get there early though because--who knows what could happen? I certainly cut things a lot closer with early morning Amtrak departures than the airport.

Supersonic is unusable over land anyway. This aircraft is designed for trans-oceanic routes, like US to Asia or Europe.

Quite hard to build a railway over the ocean.

>> Supersonic is unusable over land anyway.

A myth created because Concord came to market before the American SST. Sonic booms are not the epic thunder crashes of Hollywood fame. The Concorde going by at altitude wouldn't be any louder than a truck engine braking on a nearby highway for a second or two.

Not even remotely correct. They flew supersonic aircraft over Oklhahoma City a thousand times and basically drove the city insane and had to cut testing short when it was obviously untenable to regularly Sonic Boom half a million people for commercial aviation, let alone every large city in America.

https://en.wikipedia.org/wiki/Oklahoma_City_sonic_boom_tests

If I'm doing my calculations correct, their targeted sound pressure levels of 50-100 pascal is equivalent to 127-133 decibels, which is over the threshold of discomfort for most, and getting close to the threshold of pain.

My childhood home was in the flight path for NASA when they were given the Blackbird after it's official retirement. We also routinely had fire-retardant bombers flying eye level close enough you could read the tail numbers off with a naked eye (we were on the side of a mountain, bombers flew down the valley).

Point is: the Blackbird, flying at altitude, sounded like a tree fell on the house . Big crash/thud suddenly. The bombers, though loud, were a steady build up until they passed, then quietly faded away. The Blackbird, I literally remember leaving the house to make sure there wasn't a hole in the wall or roof.

Blackbird was a beast, literally the fastest plane out there and it never really slowed down. Compare shuttle, which came in much faster but few ever complained about its boom.

This seems bit excessive, Concorde booms were purportedly about 105-110 dB on the ground when cruising at altitude (around 60 000 ft).

I've personally only experienced sonic booms from MiG-21s. They are not painfully loud, but surely startling. They are very deep and make the windows rattle.

> their targeted sound pressure levels of 50-100 pascal is equivalent to 127-133 decibels

At what distance from the plane?

Many municipalities have laws against engine breaking because of how much noise pollution it causes, so I don't think your example works they way you expect. Especially considering this would cause that noise pollution for 10s of millions of people.

It's no myth. I'm old enough to remember sonic booms as a regular occurrence. We were used to them but they were definitely louder than a jake brake and they disturbed a much larger area.

NASA is testing new designs right now to dampen supersonic booms with an eye towards changing that regulation.

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