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Tube trains could navigate the Underground using the rules of Quantum Physics

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Re: Tube trains could navigate the Underground using the rules of Quantum Physics

#71

Post by bluGill »

123pie123 wrote: post #31

Call me sceptical, but I suspect if this works very well it will be used in weapons. Which then leads me to think the whole thing is a smoke screen, not sure why

The real problem is weapons often have power and weight limitations that don't apply to trains. So you can build large, power hungry prototypes and test them on a train. Once you work out the bugs found there you then start the miniaturization and lower power versions for where you really want it (or save a lot of money by not doing that work for something that you know can't work anyway)

Re: Tube trains could navigate the Underground using the rules of Quantum Physics

#73

Post by mannykannot »

jagged-chisel wrote: post #63
xattt wrote: post #60

Earlier quoted context omitted.

Those odometers would drift as well with wheelslip, unless they are reset any time they enter a known section.

But it’s not an odometer. It’s a sensor on the track that counts axles. The system knows the precise location of the sensor, and how far axles are spaced.

That's interesting. Do you know if they are used to keep track of the trains' positions with axle-spacing precision everywhere, or only at stations and track-section boundaries? (my somewhat cursory search suggested probably the latter.)

Re: Tube trains could navigate the Underground using the rules of Quantum Physics

#75

Post by amiga386 »

mannykannot wrote: post #73
jagged-chisel wrote: post #63

Earlier quoted context omitted.

But it’s not an odometer. It’s a sensor on the track that counts axles. The system knows the precise location of the sensor, and how far axles are spaced.

That's interesting. Do you know if they are used to keep track of the trains' positions with axle-spacing precision everywhere, or only at stations and track-section boundaries? (my somewhat cursory search suggested probably the latter.)

I don't know for certain, but they'd have to have at least one set on both tracks in each ventilation section, to enforce ventilation rules (read the rest of the article about the tunnel's ventilation management). It also points out that axle counters can sense backward movements, should a stuck train require the ones following it to reverse out of the tunnel

Re: Tube trains could navigate the Underground using the rules of Quantum Physics

#76

Post by krunck »

ACV001 wrote: post #56

Quite a dumb application of quantum physics. Cooling something to near zero, which takes energy, and is complex, and big, in order to obtain precisions which are magnitudes higher than what is necessary. As if one would use CPUs to prop up an uneven table and would boast that they use microelectronics. "Instead of relying on conventional sensors, these devices use clouds of atoms cooled to near absolute zero. At thos…

See comment by "Traster".

Re: Tube trains could navigate the Underground using the rules of Quantum Physics

#77

Post by [deleted] »

aglavine wrote: post #70
markus92 wrote: post #66

Earlier quoted context omitted.

Your capacity drops dramatically, by at least an order of magnitude if not more. The Jubilee line can do 30 trains per hour, 875 people per train is 26250 people per hour. Say an average minibus can hold 26 people, you'll literally need a thousand busses an hour to move everyone. And yes it all runs at capacity especially during rush hour.

Lets call them buses instead of minibuses and each one has the same capacity of a wagon. Instead of 10 formations of 6 wagons you have 60 buses. You have same capacity and one third of traveling time per ride.

[deleted]

Re: Tube trains could navigate the Underground using the rules of Quantum Physics

#79

Post by BigTTYGothGF »

tobylane wrote: post #51
mungoman2 wrote: post #13

Earlier quoted context omitted.

> Naturally, trains already have track-based location systems, but they are usually based on a train being within a “moving block”, so their accuracy is down to metres rather than centimetres. If you want to monitor track conditions, the more accurate the location of the suspected fault, the less time staff spend repairing it. Agree in principle though, is this extreme precision really needed?

The lines with platform edge doors (Elizabeth, half of Jubilee) do need to be in the right place with 10-20cm accuracy.

Surely this has to also be a problem long solved by classical physics?

Re: Tube trains could navigate the Underground using the rules of Quantum Physics

#80

Post by avianlyric »

bluGill wrote: post #65
BiteCode_dev wrote: post #34

Earlier quoted context omitted.

Agreed, but then said optical markers regularly positioned in tunnels and a map of the tube is enough to position yourself already. That's likely how it works right now, and it's fine.

The article says they just use wheel sensors. Most of them time they don't need to be very accurate so that is more than good enough, but in stations much higher accuracy should be needed and so they need an additional correction there. (note that I said should: I'm a strong believer in automated edge of platform doors which require stopping so the train doors align. Few systems in the world have this though)

A number of parts of the underground already have platform edge doors, and train stopping locations are tightly controlled regardless of the presence of platform edge doors.
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