I would think the biggest issues are weight (trains haul quite a bit more than airplanes can, as do ships) and being able to stay on the tracks. The train, however fast it goes, must stay on the tracks or it can not continue. The airplane has no tracks to speak of, and can do pretty much whatever it pleases provided that the intended path does not intersect with the terrain. Not having to worry about tracks or terrain, airplanes can instead focus on putting a ridiculous amount of thrust out and just hauling ass across the sky.
So yeah, as others have said, airplanes can move smaller cargoes very fast, but trains (and ships more so) can carry far more cargo in a single trip. As I recall, ocean going ships are still one of the primary methods used by the US military for moving equipment around because of this. If you plan ahead, you can have a ship full of tanks close enough to any problem spots to get there faster than the same tanks could get there traveling from the US via plane.
There was a supersonic car. It had a couple of jet engines and used 5 gallons of fuel per second. It was expensive, dangerous, and the only place you could drive it was in the desert. It was utterly useless, built only to break a record, but relatively cheap and easy to build.
You could easily have a train that is as fast as a 747. Simply take a 747, mount it on tracks and fire it up. It will go fast but it won’t do anything useful because it’s not a train. They are completely different things.
But for a possibly acceptable answer, look at thrust to weight. One site I saw said that a locomotive produces 64,000 pounds of thrust. The engine on the current 747 is the same, but it has 4 engines. A locomotive can pull a few million pounds, a 747 weighs less than a million.
Planes need a lot of thrust to get off the ground. Let’s assume a plane needs to be going around 100 mph to get enough air flow to get airborne, so just to get started on a flight requires them to go faster than anything on the ground. A jet isn’t at it’s most stable at 100 mph so once their wheels are off the ground, they need enough thrust to point the nose up and gain airspeed and altitude.
Once they level out, why not use that power to go fast? Actually, they usually aren’t trying to go fast, they are usually trying to find a speed that gives them maximum efficiency and, since they have powerful engines, that speed is pretty fast.
A train has to lug a huge load around, but it only needs to go tens of miles per hour, and it does that really well.
Here’s a test run of a French high-speed train that hit 574,8 km/h with steel wheels on rails. Note that it is quite noisy in passing. All sorts of things had to be tweaked to get it to go that fast; the test was on a new line before it opened to revenue service, and I believe the scheduled speed is less than 350 km/h. I think the new Chinese high-speed trains had a higher scheduled speed, but ran into problems.
It has been touched upon but not summarised that the other problem is “track”.
The “track” for a plane is ready made and comes (with narrow exceptions) clear and bump free. So you can do 500mph and not hit anything, and if you are thrown around a little, well, you still don’t hit anything.
The “track” for a train has to be constructed on land at tremendous cost and even then all you get is very limited “lanes” (as opposed to the sky which has thousands of “lanes”). For a very high speed train the track has to be constructed billiard table smooth despite hills, valleys, roads, houses etc etc. It has to be very closely fenced out because hitting anything sizeable at 500mph would be catastrophic (there are no cows or people at 30,000 feet). And if the track develops even a small bump throwing a train a few inches to one side it won’t be a few people hitting their heads on overhead lockers, it will be train hamburger.
I recognize the thread is talking about velocity, but what passengers care about is how much time they have to spend in travel. For air transport that includes lost time due to security, bottleneck boarding, baggage check, and weather delays. Due to TSA and similar in other countries, air travel suffers at least an hour penalty per trip at a “good” airport. Even if security screening were done for rail passengers, trains allow passengers to deal with their own luggage handling, board through multiple doors per car, train stations can be located much closer to cities than airports, and weather is less likely to be an issue.
Starting from parking at the train station or airport, even a modestly fast train will have moved a passenger 200 miles by the time an airliner pushes back from the gate.
Is it not reasonable that land based transport maintain it’s safety advantages over air transport (such as they are), otherwise why bother? A benign stop in the event of power loss is a great selling point for rail travel even if the vast majority of large airplane crashes do not involve engine failure or loss of power.
The train is constrained to it’s track and will need to stop if the track is blocked ahead. An airplane can divert it’s route or even land at another airport if the intended airport should close.
All high-speed trains are electric. The power supply is exposed to many sources of trouble and may fail at any time for reasons the train crew has no ability to inspect, control or anticipate…Lightning hitting an airport can’t cause one, much less all airplanes in the area to lose power for example, but this can happen with trains when a substation suffers a lightning strike or just a transformer failure. Not having to carry the prime mover, and being able to power many wheels with little weight penalty makes diesel power a non-starter for fast trains.
Taken broadly, do they exist? Google doesn’t seem to be producing much for me, but I’d understood that airline travel is meaningfully better in terms of safety per passenger-mile.
I fully concur that it would be a serious mistake to design trains that couldn’t safely withstand a power failure.
there are speed limit signs posted by the railroad for safe operating speeds, train engineers should obey them. airline pilots are not faced with similar constraints.
In addition to what Whack-a-Mole said, this is circular logic: Trains aren’t allowed to go as fast as aircraft because they aren’t allowed to go as fast as aircraft.
One thing that makes flying faster is that most geological obstacles have no effect on your route. you need no roads (other than a runway) or tracks. you can go over lakes and rivers and most mountains (depending on your aircraft). So even if the speed was the same the aircraft is likely to arrive at the destination sooner. Unless you are to drive up to your friends house and he doesn’t have a runway or a place for your chopper. But he is unlikely to have railroad tracks either.
High speed rail (e.g. Japan’s Shinkansen system) has a pretty impressive safety record, actually (I’m discounting China’s recent high-speed rail disaster here). The tracks are well maintained, securely fenced in, and have no grade crossings.
The linked article mentions that between Tōkyō and Ōsaka, a distance of 515 km, there are up to 13 trains an hour, with 16 cars, and minimum headways of three minutes. That’s more frequent than the Toronto subway…
