2 ms·

I'm not sure you're scaling logic checks out. You claim that a single track can transport 3 cars per second. That sounds dangerous. Cars going 100km/h, with a d

I'm not sure you're scaling logic checks out. You claim that a single track can transport 3 cars per second. That sounds dangerous. Cars going 100km/h, with a distance of roughly 5m... that will only be possible on long, straight stretches. But conventional trains already work very well on long, straight stretches. The difficult thing about scaling something like SkyTran will be transferring between tracks and merging at high-speed. But even if all of that works nicely, you're still limited by the time people take to get in and out of their cars. You'll end up with traffic jams waiting for 20 people to get out of their cars before your car can park at the station...

kragen 11y ago
All of your criticisms seem ill-founded. The actual number SkyTran is designed for is 3.2 cars per second, but I rounded down for ease of calculation. That gives you 9 meters between the fronts of cars, not 5. It turns out that when you can decelerate at human-body-safe 6 gees, which you can do on a SkyTran track but not a regular railroad track or street, then you can stop from 100 km/h in 6.6 meters. As I've explained above, although conventional trains do work on long, straight stretches, they do not in fact work very well for short-range trips, delivering end-user speeds an order of magnitude lower than their peak speeds. Even that they can only deliver at the cost of enormously expensive infrastructure to support the massive cars needed to make conventional trains cost-effective. Long, straight stretches are not necessary for SkyTran; you can go just as fast around curves as you can on straightaways, because the cars are suspended from the tracks. Some other PRT systems do not have this advantage. You need to keep acceleration loads manageable, but that's not difficult. Merging at high speed is a trivial problem with a centralized real-time control system. If you can ensure that cars on the same track are at given relative positions to each other, then you can just as easily ensure that for cars on different tracks that are going to merge to gether. I'm not familiar enough with SkyTran's design for transferring between tracks to know what problems you see with it. Can you elaborate? If you had everyone going to (or from) the same station at the same time, you could have station traffic jams. (And I think SkyTran's per-car capacity of 2 passengers is probably suboptimal for this reason, among others.) But since the stations are all on sidings, that only happens if you're going to the same station and there isn't a siding free at that station. You can solve this problem by going to another station nearby — I think the station spacing for most places would ideally be around 50 meters, but if that isn't enough for high-traffic areas, you could build stations there every 25, 10, or even 5 meters, thus further shortening the walk in the average case while removing the bandwidth bottleneck in the overload case.

kragen 11y ago

All of your criticisms seem ill-founded. The actual number SkyTran is designed for is 3.2 cars per second, but I rounded down for ease of calculation. That gives you 9 meters between the fronts of cars, not 5. It turns out that when you can decelerate at human-body-safe 6 gees, which you can do on a SkyTran track but not a regular railroad track or street, then you can stop from 100 km/h in 6.6 meters. As I've explained above, although conventional trains do work on long, straight stretches, they do not in fact work very well for short-range trips, delivering end-user speeds an order of magnitude lower than their peak speeds. Even that they can only deliver at the cost of enormously expensive infrastructure to support the massive cars needed to make conventional trains cost-effective. Long, straight stretches are not necessary for SkyTran; you can go just as fast around curves as you can on straightaways, because the cars are suspended from the tracks. Some other PRT systems do not have this advantage. You need to keep acceleration loads manageable, but that's not difficult. Merging at high speed is a trivial problem with a centralized real-time control system. If you can ensure that cars on the same track are at given relative positions to each other, then you can just as easily ensure that for cars on different tracks that are going to merge to gether. I'm not familiar enough with SkyTran's design for transferring between tracks to know what problems you see with it. Can you elaborate? If you had everyone going to (or from) the same station at the same time, you could have station traffic jams. (And I think SkyTran's per-car capacity of 2 passengers is probably suboptimal for this reason, among others.) But since the stations are all on sidings, that only happens if you're going to the same station and there isn't a siding free at that station. You can solve this problem by going to another station nearby — I think the station spacing for most places would ideally be around 50 meters, but if that isn't enough for high-traffic areas, you could build stations there every 25, 10, or even 5 meters, thus further shortening the walk in the average case while removing the bandwidth bottleneck in the overload case.