There are, idk exact fugure, many thousands miles of large diameter pipes for natural gas, oil and other stuff at high pressure without any unsolveable problems with leaks and containing pressure. Pipe with vacuum is even easier, since atmospheric pressure will auto-seal most small leaks and you need thinner pipe walls since pipe wall will work with compression instead of stretching when higher pressure is outside the pipe.
Vacuum is nothing exceptional. It is just 1bar pressure difference. It is nothing for modern technology.
So, there are no technical porblems at all to build a parallel pair of thousand miles pipe that will easily stand that funny 1bar pressure difference.
The limitations are the same as for railroads. But with pipes you have no friction, no occasional obstacles and no weather dependence. Vacuum pipe transport easily could be much cheaper in exploitation than railroads.
Airlocks does not work in the way that re-pressurize tube. Vessel enters airlock chamber through first door, chamber depressurized and only after that, second door to the tube is opened. No vacuum lost in pipe. On arrival the process is reversed.
requires countless costly and high maintenance pumping stations to consonantly monitor and re-pressurize etc etc.
There are no countless costly and high maintenance stations on gas pipes of thousands kilometers across Russia. There are compressor stations every few hundreds kilometers, but they needed to fix the pressure loss due to friction of gas against the pipe walls. There are no need to have that stations for vacuum. To detect leaks, simple chain of internal pressure sensors along the tube is enough. If there will be some leak, closest sensor willl show highest pressure, so leak will be located instantly.
speed rail like in China or Japan is far more effective,
Any transport is effective in transportation.
efficient,
Highly doubt that. You have to continously spend part of energy to fight air friction.
less dangerous,
Questionable. Since rail is open, there could be occasional obstacle on the way. If speed is high, result could be very bad.
If vacuum tube is damaged, vessel is just slowly stops long befor the damage, due to incoming air pressure and friction.
carries more payload
As far as I know, any maglev is limited in payload.
and can tolerate stops
That is true. Occasional stop in vacuum tube will be more problematic, like in underground subway.
as opposed to hyperloop.
Hyperloop is a failed implementation (at least for now) with strange approach of using air cushion for hovering inside vacuumed tube (?).
Vacuum tube transport is very old idea, from the beginning of XX century. Just like with electric car on batteries there is absolutely nothing new, but unlike battery cars, humanity have all necessary technologies for a long time. The question is only in money to build a large scale commercial system. There was many attempts to buld vacuum transportation system, but first ones (in Russia and Britain, IIRC) was cancelled by WW1, second ( in Third Reich ) was cancelled by WW2, however in 1960-s some Japaneese engineers buld a working proof of concept and got the speeds up to 2000kmh. The problem was with high acceleration of prototype, animals they use for tests died due to high G. Don't remember how the Japaneese story ended, I read that long ago.
Hyperloop is not the only current project of vacuum tube transport. China currently working on vacuumized railroad with speeds up to 1000kmh, f.e. Just that Musk's hyperloop is most hyped, as everything Mask's.
There are, idk exact fugure, many thousands miles of large diameter pipes for natural gas, oil and other stuff at high pressure without any unsolveable problems with leaks and containing pressure. Pipe with vacuum is even easier, since atmospheric pressure will auto-seal most small leaks and you need thinner pipe walls since pipe wall will work with compression instead of stretching when higher pressure is outside the pipe.
Vacuum is nothing exceptional. It is just 1bar pressure difference. It is nothing for modern technology.
So, there are no technical porblems at all to build a parallel pair of thousand miles pipe that will easily stand that funny 1bar pressure difference.
The limitations are the same as for railroads. But with pipes you have no friction, no occasional obstacles and no weather dependence. Vacuum pipe transport easily could be much cheaper in exploitation than railroads.
Gonna need a very durable seal
Airlocks does not work in the way that re-pressurize tube. Vessel enters airlock chamber through first door, chamber depressurized and only after that, second door to the tube is opened. No vacuum lost in pipe. On arrival the process is reversed.
There are no countless costly and high maintenance stations on gas pipes of thousands kilometers across Russia. There are compressor stations every few hundreds kilometers, but they needed to fix the pressure loss due to friction of gas against the pipe walls. There are no need to have that stations for vacuum. To detect leaks, simple chain of internal pressure sensors along the tube is enough. If there will be some leak, closest sensor willl show highest pressure, so leak will be located instantly.
Any transport is effective in transportation.
Highly doubt that. You have to continously spend part of energy to fight air friction.
Questionable. Since rail is open, there could be occasional obstacle on the way. If speed is high, result could be very bad. If vacuum tube is damaged, vessel is just slowly stops long befor the damage, due to incoming air pressure and friction.
As far as I know, any maglev is limited in payload.
That is true. Occasional stop in vacuum tube will be more problematic, like in underground subway.
Hyperloop is a failed implementation (at least for now) with strange approach of using air cushion for hovering inside vacuumed tube (?).
Vacuum tube transport is very old idea, from the beginning of XX century. Just like with electric car on batteries there is absolutely nothing new, but unlike battery cars, humanity have all necessary technologies for a long time. The question is only in money to build a large scale commercial system. There was many attempts to buld vacuum transportation system, but first ones (in Russia and Britain, IIRC) was cancelled by WW1, second ( in Third Reich ) was cancelled by WW2, however in 1960-s some Japaneese engineers buld a working proof of concept and got the speeds up to 2000kmh. The problem was with high acceleration of prototype, animals they use for tests died due to high G. Don't remember how the Japaneese story ended, I read that long ago.
Hyperloop is not the only current project of vacuum tube transport. China currently working on vacuumized railroad with speeds up to 1000kmh, f.e. Just that Musk's hyperloop is most hyped, as everything Mask's.