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Using GPS To Prevent Train Crashes In India
dave420 writes "The BBC has an article outlining plans in India to use GPS technology to alert train drivers of obstructions on the tracks, automatically stopping the train if the driver fails to take action. This sounds like a good use of cheaply-available technology to provide a safer train network."
The reason that GPS is not used in the US for trains more is because many times tracks run right next to each other and sometimes trains run on the right and other times on the left. GPS is not accurate enough to tell what track the train is on.
Indian Railways has over 62,000 route kms of track.
Indian Railways employs about 1.6 million people.
Carries over 11 million passengers & one million tonnes of freight everyday. (about 4.83 billion passengers and 492 million tons of freight per year)
It runs about 13,000 trains daily and has 6,984 railway stations.
The longest journey on Indian Railways is from Jammu Tawi to Kanyakumari, a distance of about 3,751 kms covered by Himsagar Express in about 66 hours.
Wont matter. Most professional GPS systems use a ground radio beacon. Given that you have a known point, the beacon sends out the corrected data back to you.
While this does seem like a very practical, important, and just plain cool use of GPS, I do see the one big, ominous problem of the US jamming/degrading the GPS system in the event of another war. As well they should, but this could be leathal for this technology.
From gge.unb.ca:
The GPS Standard Positioning Service (SPS) uses the C/A-code component of the GPS L1 signal which is transmitted on 1575.42 MHz. The C/A-code, which stands for coarse/acquisition-code, is a pseudorandom noise code which the GPS receiver uses to determine the distance to a satellite. The distance is determined by aligning the received code with a replica of the code generated in the receiver. By measuring at least four such distances to different satellites simultaneously and knowing where the satellites are from the navigation messages they transmit, the receiver can figure out where it is. The C/A-code is a relatively short code which repeats every millisecond and a GPS receiver can easily lock onto or acquire it.
The military's GPS capability is known as the Precise Positioning Service (PPS). It relies on a much longer code called the P-code (for precise or precision) which is transmitted on both the L1 frequency and the L2 frequency at 1227.60 MHz. The P-code is encrypted (and it's then called the Y-code) so that it cannot be accessed by unauthorized users. Encryption also prevents a military GPS receiver from being fooled or spoofed by a fake GPS signal transmitted by an enemy. The encryption process is known as Anti-Spoofing. Military GPS receivers have decryption capabilities which permit them to recover the P-code.
Each satellite's unique P-code segment is one week long. In order to determine the distance to a satellite using the P-code, the receiver must align a replica of the code it generates with the arriving code.
Prior to 2 May 2000, the accuracy afforded users of the GPS Standard Positioning Service (SPS) was purposefully degraded through a policy and technique known as Selective Availability (SA). The use of SA gave military users of GPS a position accuracy advantage - one it did not wish to share with potential adversaries. SA was effected by manipulating or dithering the output of each GPS satellite's active atomic clock. This clock controls the generation of all of the satellite's signals and hence the measurements made by a GPS receiver. SA was imposed at a level which would yield a stated SPS horizontal (latitude and longitude) accuracy of 100 metres or better 95 percent of the time for any point in the world during a measurement interval of one day. On 2 May 2000, by presidential decree, the level of SA was set to zero. SPS users immediately saw a quantum jump in positioning accuracy with factors of 5 to 10 improvements. Even a simple handheld receiver can now often yield horizontal position accuracies of 5 metres.
Now remember, we've more or less been fighting 3rd world countries as far as their military capabilities go, so their use of GPS against us was highly unlikely. But say we go to war with a real military anytime soon. A country like China could sustain a global conflict for a while, and has the technology to make effective use of GPS against us. It wouldn't suprise me then if the (useful) SPS signal soon after the start of a conflict of that scope became non-exist.
So, back to the point of this, unless the US gives the Indian government military grade GPS gear, there could be a disaster waiting to happen. Granted, the chances are low, but still something to think about. But even given this, I personally think this should be a good model for other advanced railway systems to look at.
Request: ECM unit, 1000 km fullerene cable, 1 tactical nuclear weapon. Reason: Birthday party for foreign dignitary.
Sadly, just rebuilding the oldest parts of the railway wouldn't help with things like the 760km Konkan Railway down the west coast from Mumbai to Mangalore. The problem with the Konkan isn't that it's old, it's very new. Rather, the key issue is corruption.
If you don't check the contractors building the bridges, tunnels, cuttings, embankments, they WILL use 9 parts of sand to one of cement and bill as if they'd used 3:1. And they DID come up with a route running not inland as previously specified in the Indian Railways Engineering Code, but rather closer to the coast (through the swamps, the estuaries, the Western Ghats (mountains)), thus creating the need for hundreds of lucrative contracts for bridges, tunnels, cuttings and embankments, each of which yields a percentage in baksheesh, and each of which can then be built on the way-too-cheap once the full price for a proper job is in the bank.
The Konkan Railway thus loses USD3.5M per day and couldn't afford the planned new rolling stock, instead running aging rains at an average 50km/h instead of the promised 160km/h.
I was also surprised by the reference to "If the driver fails to do anything, then the brakes come on automatically within the next 30 seconds." as a novel contributor to safety.- I was under the impression that this device, a 'Dead Man's Handle' had been invented in the nineteenth century.
Which is not to say that I haven't had some great rides on the Konkan and met some very lovely people on the trains, because I have...
TomV
By the time the line opened on new years day 1998, there were already tens of miles of subsidence needing urgent repair.
Please read "Trains in Japan". Trains in Japan have been extremely reliable and clean since the 1950s -- almost half a century. In 1960, there was no GPS, no Internet, etc. Yet, the train system in Japan worked fine.
Japan is a smaller country.
Japan didn't have rail put in by the British
Japan has a much higher literacy rate
Japan's population have one common language. India's national language is English but that was only because it was the only common one educated Indians had.
Japan was high tech in the 1950. India simply was not.
Japan had western help to rebuild after the war
India was abondoned by the British some time ago, and part of Gandhi's dream was to bring literacy into India. He too felt there was no excuse for them living in 3rd world conditions. It's been a very slow going task.
Yes Europe is :) The system is called Galileo and you can find more information at the link. Slashdot also had a story.
The first satellites are supposed to be launched in 2004.
Yes.
When they are out at sea, the ballpark figure given by the scrambled signal is more than good enough to be useful, so boats never really needed a non-degraded GPS. Radio navigation towers are even found on the Great Lakes.
Sounds like a bit of a recipe for disaster to me. Do you have a lot of train crashes in the US?
Here in Australia, we have two parallel tracks throughout metropolitan Sydney (and, I presume, the same in other cities that have commuter trains). On the inter-city routes, most are served by a single track, but they use a physical token passing system to control who is allowed to be on any particular section of track at any given point in time. As the train passed from one section of track to another, they hand over the token for the section they've just left, and pick up a new one for the section they're entering. The crews are, obviously, quite proficient at passing this token (which is a serial-numbered/labelled piece of metal rod about 20cm long, and 1cm diameter, placed in a leather holder with a big metal ring for the actual transfer), they have to. If they miss the token, they have to stop the train and go back and get it!!! (They do have some devices to somewhat mechanise the actual token swap at some stations/in some cases, but it's still a very interactive process.)
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