Also - It's important to remember that PTC is a non-vital "overlay" to existing signal or train control systems. It will not, on its own, increase speeds or capacities. Speed is generally constrained by class of track, "curviness" of the ROW, and limitations imposed by the signal system (i.e. it may not be able to support the desired speed if the safe braking distance from top speed to zero exceeds the provided stopping distance).
Railroad Forums
Amtrak: PTC Mandate, Progress System Wide
- Discussion related to Amtrak also known as the National Railroad Passenger Corp.
Moderators: GirlOnTheTrain, mtuandrew, Tadman
This may be a mandate from Washington that Washington might not pay for. Let's remember that, if so, it's hardly new. There may have been 637 mandates by now forced on industry, local governments, schools, etc.
Okay, a really brief primer on PTC:
1) It is NOT "billions of dollars more costly" than what railroads are doing now. In fact, railroads are spending to replace existing CTC (with new CTC, same functionality) at a rate of $500 million or so per year (the number is from railroad R-1 reports to STB). Over the next 20 years, at that rate of spending, railroads will replace all the existing signal systems on the 65,000 route miles of signaled track -- for a total cost of more than $9 billion.
2) Replacing the CTC with PTC instead would cost less than $8 billion (these numbers are from a cost/benefit analysis I did for FRA in 2004, and which went to Congress).
3) PTC, whether "overlay" or replacement, is functionally the equivalent of a cab signal system, since it enforces movement authorities (hence "positive" in the name). As such, it would allow railroads to operate at higher speeds -- on Class V track, 90 MPH for passenger trains.
4) FRA has written implementing regulations for PTC -- that was done about three years ago.
5) This is NOT an "unfunded mandate" (notwithstanding Mike Ward's reference to it as such at a conference last week). No, the improvement in safety won't justify it, but does it really need justification if it's cheaper than replacing the existing control system?
6) The equipment needed for PTC can also provide information that can be used to better manage the railroad, allowing for greater capacity, better equipment utilization, more efficient scheduling of time on track for work gangs -- these benefits are substantial. In the 2004 report to Congress, they were estimated at more than $2 billion *annually*.
Seehttp://www.tsd.org/papers/FRA%20PTC%20f ... -16-04.pdf
1) It is NOT "billions of dollars more costly" than what railroads are doing now. In fact, railroads are spending to replace existing CTC (with new CTC, same functionality) at a rate of $500 million or so per year (the number is from railroad R-1 reports to STB). Over the next 20 years, at that rate of spending, railroads will replace all the existing signal systems on the 65,000 route miles of signaled track -- for a total cost of more than $9 billion.
2) Replacing the CTC with PTC instead would cost less than $8 billion (these numbers are from a cost/benefit analysis I did for FRA in 2004, and which went to Congress).
3) PTC, whether "overlay" or replacement, is functionally the equivalent of a cab signal system, since it enforces movement authorities (hence "positive" in the name). As such, it would allow railroads to operate at higher speeds -- on Class V track, 90 MPH for passenger trains.
4) FRA has written implementing regulations for PTC -- that was done about three years ago.
5) This is NOT an "unfunded mandate" (notwithstanding Mike Ward's reference to it as such at a conference last week). No, the improvement in safety won't justify it, but does it really need justification if it's cheaper than replacing the existing control system?
6) The equipment needed for PTC can also provide information that can be used to better manage the railroad, allowing for greater capacity, better equipment utilization, more efficient scheduling of time on track for work gangs -- these benefits are substantial. In the 2004 report to Congress, they were estimated at more than $2 billion *annually*.
Seehttp://www.tsd.org/papers/FRA%20PTC%20f ... -16-04.pdf
Randy Resor, aka "NellieBly" passed away on November 1, 2013. We honor his memory and his devotion to railroading at railroad.net.
Ms. Bly and Moderators, while OT at Amtrak discussion yet relevant to PTC and the provision within RSIA '08 mandating such be installed on lines handling certain HAZMAT, would have an active PTC system avoided or minimized Weyauwega?
Amtrak related link: http://www.ntsb.gov/speeches/s980401.htm
Amtrak related link: http://www.ntsb.gov/speeches/s980401.htm
NellieBly wrote:Okay, a really brief primer on PTC:Sorry, that's simply not true. PTC does not enforce movement authorities, it enforces Stop indications, civil speeds, and optionally protects working limits. It does not convey authority for movement. The "positive" in the name means that the system enforces positive stops. It has nothing to do with conveying movement authority. CTC, track warrant, train order, timetable, or some other other method of giving trains authority to occupy main track is necessary with PTC. PTC is also not "functionally the equivalent of a cab signal system" - many implementations of it cannot discern, without the use of traditional track circuits, the position of a switch. The same can be said of the system's ability to differentiate which track a train is operating upon; it's spotty at best without supplementation by another, vital system. It also cannot "do" interlockings.
3) PTC, whether "overlay" or replacement, is functionally the equivalent of a cab signal system, since it enforces movement authorities (hence "positive" in the name). As such, it would allow railroads to operate at higher speeds -- on Class V track, 90 MPH for passenger trains.
NellieBly wrote:5) This is NOT an "unfunded mandate" (notwithstanding Mike Ward's reference to it as such at a conference last week). No, the improvement in safety won't justify it, but does it really need justification if it's cheaper than replacing the existing control system?It is absolutely an unfunded mandate. Any time the government forces a private or public entity to do something that it would not, under normal circumstances, do itself, and that would cost that entity money, with little or no government financial support, it's an unfunded mandate. And it's not "cheaper than replacing the existing control system", since it cannot replace the control system, only supplement it.
Even if it could replace the existing control system, how is replacing something "cheaper"? Are you saying that dismantling a functioning signal and control system and installing a totally new one is without cost? Where is the cost recovery? In selling the hardware from the old system?
According to the Don Philips column in the latest Trains magazine, it appears that the major freight railroads were pretty much on board on this PTC thing. Some of them, e.g. UP, have already stated that they are not looking for any government funding to make this happen, while a few others have said that they will accept any help that they can get. I suspect that some financial help will be forthcoming in the various infrastructure funding projects. Actually, it seems that the ones that will need more government help are the commuter systems, specially the ones that are not already embarked on some form or another of PTC system installation already, and some of the smaller class Is. As it stands BNSF, UP, CSX and NS were already sort of heading in this direction for various reasons anyway. The only quibble appears to be whether it must be done by 2012, 2015 or sometime later.
Last edited by Jishnu on Mon Dec 15, 2008 11:00 am, edited 1 time in total.
The problem with the PTC for freight railroads is that freight trains have non-standard braking profiles. On the NEC the ACSES is no problem. Passenger trains have a roughly uniform weight distribution and braking profile. They are also light weight compared to freight trains and can get stopped in a hurry. I once was on a train of M-1's that went from 80 to 0 in under 2000 feet.
Freight train engineers are highly skilled. They know how to get their trains stopped when they have 50 loads behind 50 empties or 50 empties sandwiched between 25 loads. Oh, did I mention that the actions they need to take vary depending on the track profile as well and there's also slack action to consider? The most reliable forms of PTC involve a radio beacon transmitting a distance to stop or distance to speed target that an onboard computer enforces. If current technology cannot calculate the braking profile of a freight freight railroads will have one of two choices. The first is use PTC that doesn't work in all cases. The PTC will apply the brakes, but the train isn't guaranteed not to slide past the stop signal anyway. The second is what I call the New York City Subway approach and just slow everything down until the PTC works in all situations. The danger is that Freight railroads might not care that a shipment take 34 hours to get to its destination as opposed to 30 hours. However the effect on passenger traffic will be severe as Amtrak trains get stuck behind even slower freight trains. If anything PTC has a good chance of actually slowing down Amtrak trains.
Freight train engineers are highly skilled. They know how to get their trains stopped when they have 50 loads behind 50 empties or 50 empties sandwiched between 25 loads. Oh, did I mention that the actions they need to take vary depending on the track profile as well and there's also slack action to consider? The most reliable forms of PTC involve a radio beacon transmitting a distance to stop or distance to speed target that an onboard computer enforces. If current technology cannot calculate the braking profile of a freight freight railroads will have one of two choices. The first is use PTC that doesn't work in all cases. The PTC will apply the brakes, but the train isn't guaranteed not to slide past the stop signal anyway. The second is what I call the New York City Subway approach and just slow everything down until the PTC works in all situations. The danger is that Freight railroads might not care that a shipment take 34 hours to get to its destination as opposed to 30 hours. However the effect on passenger traffic will be severe as Amtrak trains get stuck behind even slower freight trains. If anything PTC has a good chance of actually slowing down Amtrak trains.
The PTC implementations that I've seen *can* calculate the braking profile on the fly for a freight train. They are adaptive, in that they work better as the train proceeds along its way and the system "learns" how the train brakes. PTC coupled with ECP braking may actually work pretty darn well on freights.
I'd like to say that I am NOT anti-PTC in the least. However, I don't want anyone to get the impression that it is the panacea for safety, capacity, and speed. It is NOT. It will supplement existing train control and movement authority systems, not replace them. It will, once the design gets better, offer a higher level of safety than current ATC systems.
It will not result in 200 MPH Amtrak trains, or 60 trains per hour per track on the NEC.
The government requirement for the installation of PTC *is* undoubtedly an unfunded mandate, as it is the government imposing a solution upon the railroads that they might not pursue themselves, or might pursue in a different time frame, or pursue in a more measured fashion. The requirement now forces the railroads to spend money that they had not previously allocated for such a purpose. The commuter railroads in particular are in no position financially (all of the talk about increased ridership notwithstanding, NONE of them actually makes money) to invest hundreds of millions of dollars in this in such a short time frame.
That said, I am not against the implementation of PTC. I pray that it is done rationally, with an appropriate level of research, testing, oversight, and cooperation (as it looks as if the Class Is are doing now).
I'd like to say that I am NOT anti-PTC in the least. However, I don't want anyone to get the impression that it is the panacea for safety, capacity, and speed. It is NOT. It will supplement existing train control and movement authority systems, not replace them. It will, once the design gets better, offer a higher level of safety than current ATC systems.
It will not result in 200 MPH Amtrak trains, or 60 trains per hour per track on the NEC.
The government requirement for the installation of PTC *is* undoubtedly an unfunded mandate, as it is the government imposing a solution upon the railroads that they might not pursue themselves, or might pursue in a different time frame, or pursue in a more measured fashion. The requirement now forces the railroads to spend money that they had not previously allocated for such a purpose. The commuter railroads in particular are in no position financially (all of the talk about increased ridership notwithstanding, NONE of them actually makes money) to invest hundreds of millions of dollars in this in such a short time frame.
That said, I am not against the implementation of PTC. I pray that it is done rationally, with an appropriate level of research, testing, oversight, and cooperation (as it looks as if the Class Is are doing now).
ACSES is only used on the NEC. To my understanding, PTC can enforce a positive stop on any train of any length because each trains profile is built into the system. Through a series of calculations, the trains braking curve is constantly calculated which is used to alert the engineer when to begin braking.
JB9152,
PTC can be a vital overlay. It depends on what the railroad wants. Wabtec currently makes both--a vital or nonvital system.
PTC can be a vital overlay. It depends on what the railroad wants. Wabtec currently makes both--a vital or nonvital system.
Not the system that the Class Is are looking at right now - ETMS. And in fact the important part is the "overlay". It's important to understand that PTC does not replace the train control systems currently in place - it supplements them.
To my understanding, PTC can enforce a positive stop on any train of any length because each trains profile is built into the system. Through a series of calculations, the trains braking curve is constantly calculated which is used to alert the engineer when to begin braking.Just like the CBTC in use on SEPTA and the L the PTC systems will be no comparison to a human operator's skill and judgment and will result in much more conservative train handling. Do you actually think that someone is going to employ a system where the weight of each car is plugged into the computer before the train sets off? The crew will enter tonnage, number of cars and the computer will impose the worst case braking profile probably calculated for wet track so you'll get to see freight trains slow to something like 15mph immediately after passing an approach signal. Or better yet the PTC system will cause derailments by constantly dumping the air or pissing it away so that a runaway results.
I wonder what has been happening in the trials that BNSF has been running. Anyone have any insights into what is going on in those tests. I always like to have concrete information from real tests rather than strong feelings and theoretical conclusions.
The fact that it's been in testing for so many years now and still not in widespread service provides a wonderful window into its reliability. We all know what happens when a complex system is chronically having to work the bugs out.
Jersey_Mike wrote:Do you actually think that someone is going to employ a system where the weight of each car is plugged into the computer before the train sets off?No, because it's not necessary.
Jersey_Mike wrote:The crew will enter tonnage, number of cars and the computer will impose the worst case braking profile probably calculated for wet track so you'll get to see freight trains slow to something like 15mph immediately after passing an approach signal. Or better yet the PTC system will cause derailments by constantly dumping the air or pissing it away so that a runaway results.That's incorrect. While I'm not PTC's biggest fan right now (obviously), I don't think there needs to be hysteria in the opposite direction as well. The systems that we've seen (I'm a railroad official - prefer to remain anonymous so I can speak more candidly) from the Transportation Test Center and several vendors are adaptive - they start out 'worst case', but they quickly learn the actual braking profile of the train and adapt their responses to it.
Believe me, I'm much more comfortable with proven technology like the good ol' track circuit, and wayside/cab signaling, but if they can make this work it will make railroad operations safer. It will not, though, as I keep pointing out (and in reference to the title of this thread) make trains much faster or increase capacity, because PTC is not a full solution - it still needs track circuits and train control as it is an overlay.