Positive Train Control

Well, does PTC really add anything desireable beyond positive stop?

And, seriously, why can't a proven, in use system like LZB or TVM just be used. No reason Amtrak/FRA/etc should pick up the tab developing this stuff. They've been in use for years and increase line capacity/speeds, and bring a lot of other features to the table, both in terms of collision prevention and human interface.

As for enforcing a positive stop at a specific, fixed point, Indusi, etc have been around for 6 decades now. Even if they're 'only' 99% effective (And I suspect the actual number's significantly higher), is preventing better than 99% of the collisions that are otherwise preventable really that bad? And they're pretty cheap, anyway.

Then again, with RFID technology getting as tiny/cheap as it is, I wonder if the GPS based approaches are even worth developing - we're seriously talking about RFID chips being cheap enough to be bar code replacements. When they're THAT cheap, you could slap one every 5 or 10 ties (or less or more, as needed). Is such a greater stopping /speed change precision really needed? The wayside system could tell the trainside to ensure a stop by transponder XYZ, each RFID chip can tell the train computer who it is (figure a 128 bit serial code) and how far to its peers.

This was science fiction 30 years ago. It's theory today. It could easily be a $1 tie tack 5 years from now....

Nasadowsk wrote:
This was science fiction 30 years ago. It's theory today. It could easily be a $1 tie tack 5 years from now....

There is no need to invent new signalling systems. Just buy one of the standard European systems.

Nasadowsk wrote:Well, does PTC really add anything desireable beyond positive stop?

It grants main track authority. It maintains safe spacing increasing capacity, and allowing higher speeds. It knows temporary slow orders and timetable orders and enforces them. It protects on-track workers who hold Form-D's or Form-B's. It allows Control/Dispatch to know where the train really is in real time, even in dark territory. It enforces not only stop, but restricted speed as well. I am assuming it can also be programmed to enforce XH type orders for grade crossings.

As far as I am concerned, especially in dark territory, it would be a blessing.

First, can somebody pleas post a quick glossary of abbreviations here, as I think I am confusing some of the terms and technology, apparently.

Secondly, I have to observations. Don't base everything upon what Amtrak has for a budget. The fact is that something has to be done, and whether that is Amtrak paying for it, private industry paying for it, or the government paying for it, if there is enough public demand the money will be found. For that matter, Amtrak doesn't have the money to even run right now, so tdoies that mean we just give up and shut it down?

Also, while advanced signalling systems are great, they are still dependant upon old fashioned blocks and timiing. I think a more proper control system would radically change the whole system, with each and every train under guidance (maybe not remote control) from a traffic center which is telling each train what it may and may not do. This may be a little much for traditional engineers, but I think it is something that eventually has to happen if we are to increase capacity.

cloudship wrote:First, can somebody pleas post a quick glossary of abbreviations here, as I think I am confusing some of the terms and technology, apparently. ...

I asked Otto about this several months ago. He said there is plenty of info on the Internet, just make a search. It's good advice, just type in a term such as, "what does RFID mean?" in a search engine such as www.google.com, as I did, & get pages of results -- see one now:

From: http://www.rfidjournal.com/faq

What is RFID?
Radio frequency identification, or RFID, is a generic term for technologies that use radio waves to automatically identify people or objects. There are several methods of identification, but the most common is to store a serial number that identifies a person or object, and perhaps other information, on a microchip that is attached to an antenna (the chip and the antenna together are called an RFID transponder or an RFID tag). The antenna enables the chip to transmit the identification information to a reader. The reader converts the radio waves reflected back from the RFID tag into digital information that can then be passed on to computers that can make use of it.


How much does an RFID tag cost today?
Most companies that sell RFID tags do not quote prices because pricing is based on volume, the amount of memory on the tag and the packaging of the tag (whether it’s encased in plastic or embedded in a label, for instance). Generally speaking, a 96-bit EPC tag costs from 20 to 40 U.S. cents. If the tag is embedded in a thermal transfer label on which companies can print a bar code, the price rises to 40 cents and up. Low-frequency transponders in glass capsules are about $3.50 each and a transponder in a plastic card or key fob can be $4.00 or more. High-frequency transponders range from about $2.50 (in a card) to $6.00 or more (for a key fob or other special form factor).

But there seems to be multiple uses of the same acronym. For instance I am still confused on what people think PTC (as Positive Train Control) is and does, as there seems to be conflicting information out there. And some ofthe other systems, such as RFID as you describe, make little sense as part of a identification system when a train is rolling over them - that is way out of the bounds of that type of transmission. But is there another RFId technology that you are discussing here?

There are several proposed standards out there: NAJPTC, ITCS, ACSES, ASES, CAS, and OTC.

See 1.

The problem with some of these systems is that they try to solve everything at the same time. In reality, tracks are going to be upgraded in an incremental fashion.

On tracks which already have signals, adding cab signals via coded track circuits could be as low as $432,000 per track mile (see SEPTA's Glenside to Lansdale Signal Improvements). A new signal system is about $1 million per track mile.

You could start incrementally adding high-speed tracks now, or you could wait, possibly forever, for some vaporware system that promises to fix everything.

cloudship wrote:This may be a little much for traditional engineers, but I think it is something that eventually has to happen if we are to increase capacity.

From the standpoint of others who run in cab signal territory, it is what we call a failsafe. It is easy to learn, and gives you some satisfation that you know what is ahead. No matter if you run a 50 mph coalie, or 70 mph stacker knowing what lies ahead is important. And rather than wait for the next block signal around the curve, your cab signals tell you what lurks (or in a better case, does not lurk) ahead.

PTC or what ever form it takes, adds to your situational awareness factor as it can inform you of slow orders and the like. Far more efficient than paging through bulletins looking for slows or work areas (which can change minute by minute).

The PTC you're describing is only the NAJPTC (North American Joint Positive Train Control), as far as I can tell. That's not the only one out there, and it's still only in testing phase. The other systems include:

The Amtrak Chicago to Detroit route uses ITCS (Incremental Train Control System), which the NTSB page says is going to run at 110 MPH.

The Amtrak NEC uses ACSES in combination with the coded track circuits that have been there for decades. SEPTA, Metro-North, LIRR, NJT, and a few others use coded track circuits. The main disadvantage of this system is cost: around $1 million to $2 million per mile of double track.

As somebody who's spent a good part of the last 20 years working on PTC-related issues, let me correct a few misconceptions.

1) PTC is very expensive. Actually, equipping the *entire US Class I network* might cost $4.5 billion, but that would avoid about $6 billion in costs that would otherwise be incurred to modernize the existing signal system.

2) ALL trains on the NEC are *already* required to have cab signals with enforcement (ever since the accident in 1987). So just require PTC instead.

3) Cost to equip a loco, from the factory, with PTC is on the order of $25,000. Cab signals with enforcement probably cost more.

HoggerKen has it exactly right. It's time to ditch 1920s technology and move to a control system that adds capacity and simplifies the problems associated with moving trains running at very different maximum speeds.

It's high time railroads actually moved into the 21st Century with all the rest of us.

HoggerKen wrote: Since I ran with cab signals before, I trust them more than I would waysides any day of the week. Far safer than wayside since it enforces compliance with restrictions and signals.

Who do you work for buddy? How much did you work with them really? The system sucks, in my ten years ive saw/heard ALOT more problems then the way side signals. I've only heard one false clear block broadcasted over the radio, and heard of two stories from years ago. I "heard" the CNW system is especially horrible, the Enforced 40 MPH once you pass a flasher, throws you into suppression.

What they learned me in hog school was the UP hates cab signals but the FRA wont allow them to remove a "Safety Device" with out replacing it with something better. If it wasnt for that they would have pitched it many years ago.

As far as the puck system idea,,,,lol go watch an RCL switch engine pull up a lead with a cut. More then once i had to go get another RCL unit to drag the screwed up one off the lead, its got all the whistles and bells, GPS and whatnots. "GPS failure" "Pull back protection failure" "Transponder failure"


Micro waves cause cancer, beaming that crap at you for 12 hours, that ain't good.

UPRR engineer wrote:

Who do you work for buddy? How much did you work with them really? The system sucks, in my ten years ive saw/heard ALOT more problems then the way side signals. I've only heard one false clear block broadcasted over the radio, and heard of two stories from years ago. I "heard" the CNW system is especially horrible, the Enforced 40 MPH once you pass a flasher, throws you into suppression.

I work for UP in Iowa. My current assignment is in the Mason City yard. I got all my training on the Overland Route from Fremont to Clinton.

As far as CNW's ATC, it is not all that bad. This is because most of the E/W main was dark, 9.14 territory. The islands of CTC that did exist were only near junctions or terminals.

ATC is a two signal operation, clear and restricting. Upon a restricting cab signal, you must reduce speed below 17 mph, and acknowledge it. Should you not the high speed whistle will sound, and a brake pipe reduction must be made or in 40 seconds it goes into suppression.

Today, UP has constructed lots of new CTC from the west end of Iowa all the way to Marshalltown, with more islands beyond that. It is there intention to have CTC all the way across Iowa.

ATC is affected by excessive ground moisture. The signal on the rail will go from High to Low because of a leakage to ground. Today, that is not nearly an issue since in the last few years, new cement ties have been installed on #1 track, and new wood ties and undercutting has taken place on #2. I believe there are still spots near the Iowa River that will give you "rain control".

Back when the SD90/43AC's were new, there was a small problem with the software that caused the AC motors to give you a false low or restricting cab signal. (i.e. noise) That issue has since been solved.

What they learned me in hog school was the UP hates cab signals but the FRA wont allow them to remove a "Safety Device" with out replacing it with something better. If it wasnt for that they would have pitched it many years ago.

While UP may not like ATC, they have invested a lot of money in purchasing power with it installed. Everything since 1995 to be exact. What counts is the hundreds of CNW territory hoggers (800+ in Iowa) who think it is worth it in gold. If you measured ton miles per incident, it would be quite low.


And yes, there was one incident at the Kate Shelly High bridge in 1999 where they got a false clear cab signal. (train was stopped waiting for a movement on track #1 to clear the bridge) Scary as it was, it could not be reproduced, and no one knew exactly what caused it.