Positive Train Control and High Speed Rail

One thing for sure is it won't be one thing. It will be what it needs to be for each railroad.

The big 4 class 1's made some joint announcement in October for some common solution because of how much runthrough power there is. The commuter lines in the NorthEast will surely go their own way (most likley with ACSES), so the real question becomes if the Big 4 can get a common CTBC system working all across the country. I think in they desperately want something that is solely a locomotive cab upgrade and doesn't involve field equipment. I suspect one possible outcome would be a less than vital GPS system that may lose sync from time to time, but is backed up by the existing signaling system so the trains don't have to do the old stop and go. It all depends on the final form of the regulations.

For those interested in actually reading the proposed regulations, here's the link to FRA's proposed rule:

http://www.setonresourcecenter.com/Regi ... -17184.pdf

As for characterizing the WMATA accident as "a failure of train detection, not of the signal system", you have to have a pretty sharp knife to split hairs that finely. A train control system that loses track of where the trains are isn't of much use to anyone.

As for characterizing manual block as a "signal system", I suppose that's technically correct, in the same sense that mechanical trip stops might be called "positive train control". But the point of my original post is that what FRA means by the term "Positive Train Control" is something quite different than conventional fixed-block signaling or even a system such as ACSES or the European Train Management System. Read the rule.

But the point of my original post is that what FRA means by the term "Positive Train Control" is something quite different than conventional fixed-block signaling or even a system such as ACSES or the European Train Management System. Read the rule.

I did, PTC is described as a set of safety performance targets of which ACSES is explicitly mentioned as implementing. The document also explicitly says that the FRA does not want to set any technical specifications, only performance targets. Read the definition, its basically stop and speed limit enforcement. You can do that with trip stops and timers.

A train control system that loses track of where the trains are isn't of much use to anyone.

Then why are you such a proponent of CBTC? That's all it does.

Hopefully congress will be persuaded to reverse its hastily written mandate before too many billions of dollars are wasted.

As an amateur observer, I can't help but find it fascinating that some of the same players on the same board will a) complain about the idiotic restrictions of the FRA that prevent us from having fancy lightweight high-speed European passenger trains, and then b) state that they are shocked, shocked that anyone would even think of Breaking The Law By Speeding!

We all know that, when it comes to highway speed limits, the law is an ass. It's only because the government has yet to come up with a practical way to physically enforce it on everyone that we're still able to get where we need to go in a reasonable time. Does anyone actually drive 10MPH in a school zone? Of course not.

I have absolutely no claim to technical engineering knowledge that modern regulations setting railroad speed limits are too low - but I can't help but notice that passenger trains ran faster before our grandfathers were born. For every life you save by being extra-careful, you're stealing an hour of life each from thousands who now have to spend longer sitting on a train (car, bus, plane, whatever) because you slowed everything down.

Where's the right tradeoff? I have no idea - but I can't imagine that the current tradeoff is the best one, seeing that people find it better to drive at 80mph on the freeway which we all know is far, far more dangerous than taking the train.

If PTC speeds up passenger trains, it will save lives. If it slows them down, it will cost lives. And if anyone puts in a new system without doing a limited real-world test first to find out exactly what the effects are, they're not fit to be running anything. It's hard to imagine a group of people less qualified to make that decision, than our Congress.

So I have been reading through the document and look what I found on page 55.

At present, the PTC systems
contemplated by the railroads, with the
possible exception of PATH, would not
increase capacity, at least not for some
time. If the locomotive braking
algorithms need to be made more
conservative in order to ensure that each
train does not exceed the limits of its
authority, PTC system operation may
actually decrease rail capacity where
applied in the early years. Further
investment would be required to bring
about the synergy that would result in
capacity gains.

Looks like even the FRA agrees with me. Trains will probably end up going slower due to PTC. Even more good news, if trains have a PTC failure they have to drop to 30mph in DCS territory, 60 in block and 80 with CSS. If they try to adopt CBTC just slap a big old 30mph sign on the country.

The good news was that the FRA is requiring broken rail detection for passenger lines with speeds over 60mph, which means they don't intend for track circuits to be going anywhere. More good news is that any wireless communications will be using good crypto with proper key management and revocation. It's good news because key management and PKI is a major pain in the ass, which makes coded track circuits and track mounted transponders more attractive.

As an amateur observer, I can't help but find it fascinating that some of the same players on the same board will a) complain about the idiotic restrictions of the FRA that prevent us from having fancy lightweight high-speed European passenger trains, and then b) state that they are shocked, shocked that anyone would even think of Breaking The Law By Speeding!

I don't complain about the crashworthniess standards. It is cheaper to make stronger to make passenger stock cheaper than to try to rubberize the right of way.

I read through the regulations and I would have to say that the biggest problem besides increasing the scope beyond passenger and TIH lines is how PTC failures are handled, especially considering how the industry is going for something resembling CBTC with central servers and whatnot. On lines where PTC might be present with an existing signaling system the FRA seems to take the position that 2+2 = 2 assuming that if the PTC fails the sky will fall and trains have to slow down to 30mph, then travel 60/50 under ABS or 80 under cab signals with ABSOLUTE BLOCK PROTECTION. Oh, and if there;s no ABS present the train is stuck at 30mph the WHOLE WAY. Thank god wireless communications and computer servers and networks NEVER FAIL or this might become a huge problem. They are forgetting that where other safety systems are present PTC's benefit only appears in aggregate. If a train doesn't get its PTC datagram when it passes a green signal the engineer should just act on the signal indication. Same if the single-point-of-failure back end servers fail or a transmission tower gets hit by lightning or a track transponder fails.

The FRA also needs to take the opportunity to dump all of the mentions of 79 and 59 mph and just raise them to 80 and 60.

Here's a good presentation on the ITCS signaling currently installed on the Amtrak Michigan Line which is the prototype of the PTC system the major railroads want to install.

http://www.arema.org/eseries/scriptcont ... m_2007.pdf

The document dates from 2007 and AFAIK the 110mph service still hasn't started and Amtrak recently received stimulus money to finish updating the system. Note the main "problems" have to do with the radio links between everything despite the geography of the Michigan Line being flat and devoid of tunnels. I still am unsure how the on board computer knows which track it is on. The one good news is that the control servers are located every 5-7 miles apart and operate independently of any central office so the whole railroad can't go down. The Michigan Line ITCS has been backstopped by a traditional wayside (and possibly cab) signaling system so any problems with the wireless stuff doesn't result in a huge delay.

NellieBly wrote:...[The] FRA issued its proposed rule requiring railroads to install PTC on all "main lines", all those that carry passenger trains, all those that carry more than five MGT of traffic, and all those that carry any TIH (toxic inhalation hazard) traffic. Implementation plans are due by next April (2010) and systems must be in place by 2015. This is real, folks.

There will be a hearing in Washington on August 13, for any of you who would like to comment (first you have to read the 304-page document describing the proposed rule).

PTC will permit operation of passenger trains at more than 79 MPH, subject to other requirements such as track safety standards. It will positively enforce train separation, and it will permit the removal of obsolete cab signal and intermittent train stop systems. Get ready for the new world!

I just finished wading through the rule in all its detail. The USDOT Office of Policy will be offering appropriate comments in due time, but all told I think FRA did a very good job of laying out the case for PTC, the costs, and the potential benefits for the freight railroads.

Some consider it an "unfunded mandate". The rule, however, makes it pretty clear that the intent is that PTC will replace existing control systems in time. In that case, the net cost to the industry will be quite small, and the potential benefits very large. And we may see lots more higher-speed passenger trains.

I'm going to be honest, I only read the Economic Analysis. That said, this is an unfunded mandate. I'm no legal expert, but I do know that unless the railroads get a decent amount of money for installing PTC it's an unfunded mandate. This is because even if there are long-term cost savings, PTC installation is an up-front capital cost. More importantly in deciding the unfunded mandate question is this: if the railroads were to gain a huge savings from PTC, they would install it themselves without government needing to get involved. That said the solution is obviously for the government to fund PTC! In short, there needs to be a concerted grassroots and lobbying effort to make sure that this gets a fair share of the big government pie...

That said the solution is obviously for the government to fund PTC! In short, there needs to be a concerted grassroots and lobbying effort to make sure that this gets a fair share of the big government pie...

I would simply prefer a special interest lobbying effort to scale back the mandate. The FRA flat out says that PTC doesn't make economic scene and by installing CSS on commuter system you would easily eliminate a good amount of the existing risk.

Okay, so there is some mention in the documents about the unfunded mandate question:

"The proposed rule itself would not create an unfunded mandate in excess of the threshold amount. The bulk of unfunded mandate for implementation of PTC is attributable to RSIA08. The effects are discussed earlier in this document in the Regulatory Impact Analysis. Any unfunded mandates attributable to the proposed rulemaking would pertain to the costs of filing paperwork to prove compliance with RSIA08."

Okay...There is an unfunded mandate and the FRA concedes that.

Jersey_Mike wrote:

That said the solution is obviously for the government to fund PTC! In short, there needs to be a concerted grassroots and lobbying effort to make sure that this gets a fair share of the big government pie...

I would simply prefer a special interest lobbying effort to scale back the mandate. The FRA flat out says that PTC doesn't make economic scene and by installing CSS on commuter system you would easily eliminate a good amount of the existing risk.

What's CSS? I'm not so well-versed on signalling systems. Regardless I think there needs to be funding for this either way, and preferably with work done case-by-case rather than a nationwide mandate.

EDIT: Wait, CSS is short for Cab Signalling System, right? If it is then we just have some acronym confusion going on.

EDIT: Wait, CSS is short for Cab Signalling System, right? If it is then we just have some acronym confusion going on.

Yeah. CSS would have prevented the Chatsworth accident. It's proven technology and available for modest cost. Unfortunately the NTSB borwbeat congress into implementing their little technological wet dream.

Jersey_Mike wrote:

EDIT: Wait, CSS is short for Cab Signalling System, right? If it is then we just have some acronym confusion going on.

Yeah. CSS would have prevented the Chatsworth accident. It's proven technology and available for modest cost. Unfortunately the NTSB borwbeat congress into implementing their little technological wet dream.

Actually, I don't think CSS would necessarily have prevented Chatsworth, although it would certainly have mitigated it tremendously, since the Metrolink train would have been held to 15 mph as it approached the stop signal at TOPANGA. If the engineer had exceeded 15 mph (let alone the 40 or so he was reported to be doing), the train would have received a penalty application which would almost certainly have stopped it before reaching the signal. However, if the speed had been lower than 15, with the engineer not paying attention, he could still have passed the home signal and collided with the freight train, which had practically reached the interlocking by that time. Of course, the freight's cab signal would have dropped to restricting when the Metrolink train overran its own signal, and if the freight had been a mile or so away at the time that would also have mitigated the effects of the collision (or even prevented it if the Metrolink engineer had returned to the real world in time to notice that he had run a stop signal, and stop his own train). In the absence of cab signals, the freight train would not have had the benefit of any advance warning once it passed the previous signal, no matter how far away he was from TOPANGA. Unfortunately, since the collision happened within seconds of the time the Metrolink train overran the signal, there was no time for anything to prevent it. I hope all of the projected train-separation systems are focused on stopping a train before it reaches a stop signal, not after it has gone by it.

However, if the speed had been lower than 15, with the engineer not paying attention, he could still have passed the home signal and collided with the freight train, which had practically reached the interlocking by that time.

You're right it is not as perfect as PTC, but the cost/value ratio is remarkably better. Look at the Northeast commuter operations. Millions of passengers carried every year and not a single fatality due to a passed stop signal in CSS territory. You have a greater chance of being killed by a crazed gunman on the LIRR than you do rolling past a stop signal. PTC is a solution in need of a problem. The irritating part isn't just the cost, its that the whole technology doesn't work very well. The mandate prevents the FRA from adopting flexible regulations that would allow PTC to supplement reliable signaling technologies, but still allow it to be cut out or ignored.

ExCon90 wrote:

Jersey_Mike wrote:

EDIT: Wait, CSS is short for Cab Signalling System, right? If it is then we just have some acronym confusion going on.

Yeah. CSS would have prevented the Chatsworth accident. It's proven technology and available for modest cost. Unfortunately the NTSB borwbeat congress into implementing their little technological wet dream.

Actually, I don't think CSS would necessarily have prevented Chatsworth, although it would certainly have mitigated it tremendously, since the Metrolink train would have been held to 15 mph as it approached the stop signal at TOPANGA. If the engineer had exceeded 15 mph (let alone the 40 or so he was reported to be doing), the train would have received a penalty application which would almost certainly have stopped it before reaching the signal. However, if the speed had been lower than 15, with the engineer not paying attention, he could still have passed the home signal and collided with the freight train, which had practically reached the interlocking by that time. Of course, the freight's cab signal would have dropped to restricting when the Metrolink train overran its own signal, and if the freight had been a mile or so away at the time that would also have mitigated the effects of the collision (or even prevented it if the Metrolink engineer had returned to the real world in time to notice that he had run a stop signal, and stop his own train). In the absence of cab signals, the freight train would not have had the benefit of any advance warning once it passed the previous signal, no matter how far away he was from TOPANGA. Unfortunately, since the collision happened within seconds of the time the Metrolink train overran the signal, there was no time for anything to prevent it. I hope all of the projected train-separation systems are focused on stopping a train before it reaches a stop signal, not after it has gone by it.

Correct. Cab Signals are NOT a positive train control solution despite what the media and some of the misinformed people believe. Depending on the railroad, you can go right through a stop signal at 20mph. The only major railroad using a system on a regular basis (not experiemental) that can enforce a positive stop is Amtrak. They have it on the NEC from New Haven east to Boston. There are sections west of NYC but it's not complete yet.

The system works well. And other then light engines and shoving moves, it can prevent collisions. As of the past week, they have it setup in one area completley radio based for a speed restriction. No track mounted transponder. While it's not perfect, it's a tested and proven system.