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Re: GPS and PTC? Too much reading?
Author: Dr Zarkoff
Date: 08-25-2011 - 10:23
>I am not sure about the broken rail issue,
The FRA is very concerned with them, in fact more so than with the locational margins of error -- heard it from them with my own ears.
>It's interesting that some would seem to be okay with another Chatsworth or two per year, rather than upgrading our rail control systems with modern technologies? . . .When you see a mess like Chatsworth, and understand that all of the events were preventable with systems level overrides,
All this hoopla about PTC comes down to one thing: royalties for suppliers. With all the older signal stuff, including cab signals, the patents expired decades ago. No signal/train control system can absolutely prevent something like Chatsworth for the simple reason that no matter how slow you drive, I can always arrange to have you run over my foot. The other parts of the equation are the gentility and diligence of management supervision and the maturity and self-respect of the individual employees. With all of today's diploma-mill, off-with-their-heads officials and HRD encounter group diversity policies, it's become impossible to maintain an atmosphere of good employee work ethics, let alone detect and weed out the bad eggs. So it's much safer to get emotional satisfication, not to mention the media attention, by running around screaming "more technology, more technology" than addressing the real issues. Check into the ratio of train frequency/Chatsworth like accidents of WWII and the 1920s. From the statistics I've seen, the situation has gotten worse as train frequency has declined. This is more a human skill and self-respect issue than a technological one.
The notion of PTC-like signal systems has been visited before, in the late 1920s and early 1930s with the introduction of ATS (about 3 different kinds) and cab signals (with and without speed control). The discussions of the era are very similar to today's about PTC. Eventually, it became apparent that the expense of installation and maintenance couldn't be justified by the returns.
Signal visibility issues were deliberately left out of the Chatsworth investigation, and those SafTran color light signals can be almost impossible to see when they're not aimed correctly. They can even convey the impression of an incorrect indication. Each individual color must be aimed separately, which apparently even SafeTran doesn't comprehend, let alone RR signal departments. Over the next several months after Chatsworth, Metrolink very quietly changed all these to LED. In Australia, they have searchlight LED signals which have all three colors of LED mixed into one flat array, no fiber optics. Every LED signal I've ever seen is visible for at least a mile, day or night, from almost any angle. This can't be said of the SafTran lightbulb/fresnel lens units.
>Broken rails are detected the old fashioned way through interupted circuits.
The railroads are interested in doing away with all lineside signal apparatus (that cost businiess again), a situation which coincidentally does away with those interruptable circuits too. This is the issue, why go to all the expense of GPS when it won't do away with the lineside stuff? Condiser the rats nest of buying and maintaining all those GPS enabled locomotive units and FREDs. In similar fashion, the railroads have been trying for at least 25 years to come up with a new standard for locomotive MU cables. The problem is that there are so many locomotives, the costs of purchase and particuarly the logistics of installation are staggering, virtually unattainable. It's even worse if you contemplate changing the entire nation's fleet of freight cars to electronic brakes; IOW, it ain't gonna happen.
The FRA is very concerned with them, in fact more so than with the locational margins of error -- heard it from them with my own ears.
>It's interesting that some would seem to be okay with another Chatsworth or two per year, rather than upgrading our rail control systems with modern technologies? . . .When you see a mess like Chatsworth, and understand that all of the events were preventable with systems level overrides,
All this hoopla about PTC comes down to one thing: royalties for suppliers. With all the older signal stuff, including cab signals, the patents expired decades ago. No signal/train control system can absolutely prevent something like Chatsworth for the simple reason that no matter how slow you drive, I can always arrange to have you run over my foot. The other parts of the equation are the gentility and diligence of management supervision and the maturity and self-respect of the individual employees. With all of today's diploma-mill, off-with-their-heads officials and HRD encounter group diversity policies, it's become impossible to maintain an atmosphere of good employee work ethics, let alone detect and weed out the bad eggs. So it's much safer to get emotional satisfication, not to mention the media attention, by running around screaming "more technology, more technology" than addressing the real issues. Check into the ratio of train frequency/Chatsworth like accidents of WWII and the 1920s. From the statistics I've seen, the situation has gotten worse as train frequency has declined. This is more a human skill and self-respect issue than a technological one.
The notion of PTC-like signal systems has been visited before, in the late 1920s and early 1930s with the introduction of ATS (about 3 different kinds) and cab signals (with and without speed control). The discussions of the era are very similar to today's about PTC. Eventually, it became apparent that the expense of installation and maintenance couldn't be justified by the returns.
Signal visibility issues were deliberately left out of the Chatsworth investigation, and those SafTran color light signals can be almost impossible to see when they're not aimed correctly. They can even convey the impression of an incorrect indication. Each individual color must be aimed separately, which apparently even SafeTran doesn't comprehend, let alone RR signal departments. Over the next several months after Chatsworth, Metrolink very quietly changed all these to LED. In Australia, they have searchlight LED signals which have all three colors of LED mixed into one flat array, no fiber optics. Every LED signal I've ever seen is visible for at least a mile, day or night, from almost any angle. This can't be said of the SafTran lightbulb/fresnel lens units.
>Broken rails are detected the old fashioned way through interupted circuits.
The railroads are interested in doing away with all lineside signal apparatus (that cost businiess again), a situation which coincidentally does away with those interruptable circuits too. This is the issue, why go to all the expense of GPS when it won't do away with the lineside stuff? Condiser the rats nest of buying and maintaining all those GPS enabled locomotive units and FREDs. In similar fashion, the railroads have been trying for at least 25 years to come up with a new standard for locomotive MU cables. The problem is that there are so many locomotives, the costs of purchase and particuarly the logistics of installation are staggering, virtually unattainable. It's even worse if you contemplate changing the entire nation's fleet of freight cars to electronic brakes; IOW, it ain't gonna happen.
