Why were traditional rails chosen over maglev?

[HSTEd]

Ground Effect Trains are rather pointless really, you will struggle to get much higher speeds than conventional rails without absurd curve radii, and if you thought pointwork for maglevs was difficult to engineer.....

You can stack maglevs and conventional railways... although I am not entirely sure why you would want to. The future is probably tunnels for projects such as this anyway, it might have saved a lot of hassle for not that much extra money if HS2 had been entirely tunnelled (it could have gone for straight lines between stations without worrying about land takes).

 

[Kali]

I'm thinking you'd probably generally want magnetic guidance, so you'd end up with some sort of U shaped track and end up with something rather similar to a maglev only without the energy use and infrastructure used to actually lift the train. However you could aerodynamically guide it at speed somewhat, so I suppose you could just use a flat open area as "pointwork". Or ( while we're tossing silly ideas around ) something whacky like induction braking on one side

Not sure I really want to travel for hours in a tunnel...

 

[HSTEd]

Not sure I really want to travel for hours in a tunnel...

Not really hours.... 68 minutes to Manchester and 80 minutes to Leeds using the current alignment, which doesn't head straight from Euston to Birmingham International so is a bit longer.

 

[rebmcr]

The very-long-term future of rail travel is probably ultra-long-haul (e.g. London-New York) vacuum tunnels, allowing speeds of a few thousand km/h for most of the journey.

 

[Kali]

I think at that point you're looking at ground-effect "ships" - or if we really have to power everything electrically, nuclear powered liners.

 

[LexyBoy]

Any sort of train (or any vehicle) is inherently wasteful as it involves moving a large mass of vehicle for a relatively small mass of passenger. Electric trains are better as the fuel and generator doesn't form part of the train's mass, and maglev is better still as the motor is also offloaded.

However, best of all would be to avoid the wasted mass of the vehicle at all. Using magnets it is entirely possible to levitate people. I believe the future of transport lies in maglev lines of this type becoming personal rapid transit - just dial in your destination, don your wind-proof jacket and Biggles-style goggles and be whizzed away immediately at 700 km/h.

Alternatively, maybe we will go slow - hop into a stasis booth and let the system transfer the standardised container you're in between train, truck and boat until you're unloaded at your destination. Or maybe we'll just upload ourselves into the cloud leaving the old fashioned and hippie types with a slowly crumbling IRL infrastructure.

 

[edwin_m]

How much energy does the levitation part of a maglev use?

I'm not sure how energy-efficient PRT is, as the mass of the pod may be similar to the mass per seat of some other vehicle types. Also if it was to run at higher speeds the aerodynamic losses of many pods in quick succession would be more than those of a single vehicle having the same number of seats.

 

[LexyBoy]

I didn't say anything about a pod, my point was that we should dispense with the vehicle element entirely

How much energy does the levitation part of a maglev use?

Wikipedia reckons 1700 W/tonne for levitation and guidance, but no source is provided. In theory no energy is needed (you can use permanent magnets for levitation after all), but in practice I presume this energy is consumed by resistive losses in induced currents and in refrigeration required for the superconductors.

I also note both the Transrapid and JR systems use liquid helium - unless it can be made to work with high temperature superconductors (i.e. above -196 C) then this will be a limitation, as helium is a fossil resource. AIUI, there aren't any high temperature superconductors available now which can carry the high currents required for very strong magnets.

 

[samxool]

The very-long-term future of rail travel is probably ultra-long-haul (e.g. London-New York) vacuum tunnels, allowing speeds of a few thousand km/h for most of the journey.

no it won't be. The infrastructure costs and egineering required for that would be insane!
Journeys like that in the long term future will be low orbit air travel.

 

[cjmillsnun]

Those sonic booms came from Concorde's shock wave as it flew down the English Channel (to or from Paris), or down the Bristol Channel (to or from London) on its way to/from the transAtlantic supersonic route structure.
There was no supersonic operation over land.

Actually there was. You might want to read Brian Trubshaw's books either "Test Pilot" or "Concorde - The Inside Story" where he describes an overland supersonic route in the UK used during the test programme.

I agree there were no overland supersonic flights operated by the airlines.

 

[John07]

Why has no-one suggested jet packs?

 

[Eagle]

Because I'm not convinced that there will ever be a jetpack powerful enough to lift more than two minutes' worth of fuel.

 

[61653 HTAFC]

Why has no-one suggested jet packs?

Because they (and indeed all other modes of transportation) will be obsolete once I've perfected my teleportation device!

 

[HSTEd]

Larry Niven posited a world (in his Ringworld stories) where teleportation is effectively free and as a result the entire world has sort of merged together into a single global city without many cultural differences across it.

The other, much less obvious, prediction was that whenever something newsworthy happened, a huge flashmob would immediately appear at the location of the story to watch.

 

[Kali]

Both of those are already reality, only without any physical presence needed. The corollary of that is that passenger transport may become less and less necessary ( which is a pity as I quite like travelling, and the corollary to *that* is costs going up ).

Jet packs would be a fairly effective method of population control

 

[The Decapod]

Regardless of whether suspended by maglev or wheels, higher speeds require either super-straight routes or tilting trains. The former are difficult in a densely populated county like the UK, and I haven't heard of maglev doing the latter.

Actually they exist already - they are called 'flightpaths'.

 

[dysonsphere]

Larry Niven posited a world (in his Ringworld stories) where teleportation is effectively free and as a result the entire world has sort of merged together into a single global city without many cultural differences across it.

The other, much less obvious, prediction was that whenever something newsworthy happened, a huge flashmob would immediately appear at the location of the story to watch.

Indeed and if you happen to have a first edition of Ringworld its worth money. Larry had the earth rotating the wrong way in the dawn booth hopping chapter at the beginning. (yes im a nerd)

 

[VauxhallandI]

Well I used the Shanghai maglev and I was pleased as punch!

Even though I had to swap to Tube it saved over an hour by tube all the way.

The roads are not really an alternative as they are chock block and the taxi drivers are mental