Slashdot today had an article about plans to build a maglev between LA and LV. I love the idea of a maglev - it's very science fiction - but given the poor record of the US to actually build anything anywhere on time and on budget I think they would be better off with a TGV style railed service.
The Transrapid MagLev has a number of problems over TGV/ICE/bullet style trains:
- more expensive trackwork (by a factor of 2 or so)
- can't run on conventional trackwork, thus unable to continue at lower speed to other destinations, or to negotiate the city ends whilst direct routes are being built (See London and Madrid for examples)
- slow and complex switches: rail switches involve moving a few 100kg of steel rail a few cm, monorails (including maglev) require moving huge 100tonne segments of track many metres.
- dubious speed merits - the TGV has been matching the maglev for speed in trials, though not in commercial operation.
On the pro side, maglevs have a number of purported advantages:
- no contact: reducing wear, rolling resistance vibration and noise.
- lower drag coefficient
- no overhead wires
But these turn out to be less significant in practice because:
- wheel wear is not a major operating cost. The wheel vibration in railed vehicles can be avoided with maglev suspension in the bogies/trucks; and most vibration at high speed comes from the air (the AGV has special door handles to minimise turbulence).
- The wheels do contribute to the drag coefficient, and in fact the limiting factors for TGV speed are drag, power supply and the speed of sound in the overhead wires. But as I noted, they have matched the MagLev's speed repeatedly and there is no known reason why they can't increase the speed (especially when nanotubes become commercially available, allowing an order of magnitude increase in the speed of sound in the catenary). Increasing the operating voltage is practical to at least 50kV, at which point the rail line can start to be considered as an additional supply line.
- Overhead wires are considered by some to be unsightly, but as someone who lives next to a freeway, I can't see that roads are any more sightly. Often these people then propose having an elevated monorail line - let's replace those unsightly wires with giant concrete trackways :)