PTC in track warrant territory?

[MattW]

The other night, I read that CSX's Georgia Subdivision is due to have PTC installed. For those not familiar with it, it's track-warrant territory with some form of ABS that everyone says is too unreliable to allow trains to actually be governed solely by the signals...so I'm not sure why they even bother, but back to my main point. On lines that are either ABS or dark territory now, how is PTC supposed to work? I can understand roughly how it overlays on a CTC system and inter-operates from an architectural/operational perspective, but not necessarily something like this. Would trains still get track warrants over the radio? Would the railroad have to become in essence a CTC railroad?

Thanks!

P.S. just to clear things up, the trains seem "use" the signals because I hear them call the signals over the radio, but a lot of comments I've seen from different people in different places say that while the trains "use" the signals, separation is chiefly achieved via the track warrants, in other words, trains don't get cleared to follow another one using signals, they don't get track authority until the preceding train is completely clear of the area.

[DutchRailnut]

they would have to install a CTC system.

[Desertdweller]

If Track Warrant Rules are followed correctly, the following train not allowed to proceed until the previous train has cleared the section of track given it by the track warrant, the train separation will be maintained. I think PTC is a solution looking for a problem.

Les

[MattW]

If Track Warrant Rules are followed correctly, the following train not allowed to proceed until the previous train has cleared the section of track given it by the track warrant, the train separation will be maintained. I think PTC is a solution looking for a problem.

Les

I understood that it was possible to tell a following train to follow the preceding train on signals. I know that was possible under DTC, they just didn't do that on the line in question. Maybe that was done away with completely when CSX went to pure track warrants system-wide and not just this line.

[DutchRailnut]

Any accident investigation tells you that somewhere the rules were not followed.
Same in track warrant territory, if all rules are followed everything is peachy, if one rules is broken it just about doubled the "ohh Sh*t" factor.
If two rules are broken its just about guaranteed a disaster, for every rule in book there is a body somewhere in ground.....

[SleepyCat]

Re; PTC in Track Warrant Territory?
As of July 27th 2014 I’ve been taking pictures of the new stainless steel and utility boxes placed alongside CSX’s Georgia line subdivision and the other day I talked with someone familiar with CSX and the line. He informed they are installing PTC. They have already begin installation of PTC on their Abbeville subdivision; that line as you are probably aware utilizes CTC. However the Georgia line is a combination of Track Warrant Control and Absolute Permissive Block signaling, or ‘Poor Man’s CTC’.

A good write up for APB can be found at Carsten S. Lundsten’s website; http://www.lundsten.dk/us_signaling/abs_apb/" onclick="window.open(this.href);return false;

It is my understanding that CSX is not abandoning APB on the Georgia line but supplementing it with PTC. It’s very possible they may be implementing CBTM ‘Communication Based Train Control’ that allows a railroad to operate PTC albeit without the major infrastructure investment required for either TS or CTC. You can read about CBTM by going to a web browser and using a search engine, download the PDF under ‘home.insightbb.com/~jp333/index_files/cbtmcsx.ppt’

The more I learn the more data I will have to provide.

SleepyCat.

[MattW]

Thanks everyone for the replies. Thanks especially to you, SleepyCat. I can also add some of my own information now to yours. CSX is also doing this to the Atlanta Terminal portion of the ex-Georgia railroad. I saw a few new boxes and electrical drops from Scottdale through Stone Mountain today. I also noticed one of the intermediate signals, around 153 has been replaced! Northbound it's a pretty much standard 3-light "Darth Vader" but the southbound signal is a 3 over 2, with the lower head still turned away. Only thing I can think of is it's going to become a new control point and they're going to extend the CTC from Scottdale to around Lithonia. For those unfamiliar with the line, Scottdale to Lithonia is 13 miles of single track with literally no switches except for one 48-car storage track in Stone Mountain, but every train heading to the rest of the Georgia Sub has to get its EC-1 which is pretty pointless until it hits Lithonia since except for one, very lightly-used storage track, there is nothing.

But I had heard (see my topic up in CSX Forum) that the Georgia Sub didn't have true APB, and what I thought it had was closer to ABS than APB anyways.

The system you link to seems interesting, and from my inexperienced railfan mind, looks pretty good. What I got from that is that the line will transmit ATCS information is that still correct? Is that was CSX is going to go with on this line?

[SleepyCat]

Dear MattW;
I can only attest to what was told me years ago. In the process of preforming an amateur commuter rail study for a state representative I talked to one of the CSX crewmen replacing old Union Switch and Signal searchlight signals along the Georgia line at the Lithonia location for train meets, with newer design three aspect signals and local powered turnouts. Up until this point the Georgia line used ABS, solely manual turnouts in conjunction with DTC. In order to accommodate heavy traffic temporarily diverted from the CSX mainline Jacksonville Florida to Virginia the upgrade was necessary but, they were implementing APB or ‘Poor Man’s CTC’. I was able to talk later to another crewman and he explained to me with the removal of the old telegraph lines along the Georgia line CSX had instituted pulse code system for the railroad track circuit. I think that would be similar to the GE Electro Code system used by Norfolk Southern from Eastpoint to Fort Lee on their ‘S’ line (from Fort Lee to Macon the S line is strict TWC without signals except for the non-automatic block signal across from Clayton State Collge – see NS signal rules #312). The crewman was working on the digital repeater box located between Tucker and Stone Mountain, across from a Cemetary. This eliminated the need for burying cable as the rails themselves carry complex data. Later CSX converted the line’s DTC to TWC. No doubt additional signals will be added to the newer Darth Vader ‘flower pot’ style installed over the years in Clarkston, Stone Mountain, Conyers, Covington, Rutledge, Madison as they do not require replacement for an additional hood. And yes, I witnessed the removal of the old signal at point 153. Took pictures too. Take a look when you get a chance at the new cantilever signal bridge CSX has erected on their Abbeville line at the Brockett road crossing in Tucker. This is part of the PTC installment for that line. Correct me if I’m wrong but I can’t ever remember seeing a signal bridge on a CSX line near or in Stone Mountain. But they are prevalent on CSX’s A&WP subdivision between Fairburn and Palmetto.

SleepyCat.

[SleepyCat]

Dear MattW;
On the morning of Wednesday August 6th I drove on Ponce Deleon Avenue and paralleled the CSX Georgia Line from Scottsdale to Lithonia. I noticed CSX crewmen working on the utility box in Scottsdale and burying new orange loom to house new cabling. There was additional crewmen working on the new ‘battery housing’ box next to the ‘Darth Vader’ flower pot signal in Clarkston. The Repeater across from Melwood Cemetery in Tucker is untouched, while the next signal closest to Highway 78 has a ‘battery housing’ box dropped with nothing substantial done to it. However, several cable looms have been propped at the end of the siding pass Stone Mountain Village; one across the tracks from the existing signal where the new utility box is, one right beside the signal and one across the side street entrance close to the switch stand. I wonder if PTC (or CBTM) means the siding turnout will have to be protected by a switch lock or powered switch machine. In CSX’s presentation of CBTM that would appear to be the case. I forgot to tell you in my last post that one of the crewmen told me the signals were being installed from mile post 151 to Atlanta. Milepost 151 as you may know is the location of the approach (last) signal along Stone Mountain Lithonia road before the Lithonia train meet siding and a new utility box has already been dropped there. My next question is how PTC will affect the TCS (Traffic Control System – Traffic locking http://www.lundsten.dk/us_signaling/signalbasics/" onclick="window.open(this.href);return false;) that CSX has between Scottsdale and Kirkwood Interlocking, where the Abbeville subdivision joins the Georgia subdivision.

Keep me abreast!

SleepyCat.

[MattW]

Thanks again for the wealth of information you have provided! Funnily enough, I read your latest post while driving the same route earlier today (well, technically riding) You are correct, there has not been a signal bridge between Conyers and Scottdale since the middle 90s (when I begin driving along this segment extensively), but I did see the new one in Tucker, and in fact made a trip from Tucker to Athens to document the progress of the new "Darth Vader" installation. It's interesting to see that they're installing new signals from 151 all the way to Atlanta, it sounds like they're doing what I mentioned a few posts up and extending the TCS/CTC to but not including Lithonia, it makes sense to me, less paperwork for everyone. What I don't understand is the choice of signal for 152.9. Based on information and a conversation I had with Jersey_Mike on his Position Light blog, CSX is generally upgrading its controlled signals to be able to show restricting to enable trains to follow each other a bit more closely and so dispatchers don't have to "talk" the train by and that would seem to be the only aspect it can display with that second head (only one that would make sense anyways). So I'm curious if they're making 152.9 the last controlled signal (same function as Scottdale currently has) or if they're planning on making the final controlled signal 151. 151 didn't appear to have anything but the box dropped off, and it wasn't installed yet, so I don't doubt they aren't finished with it, but I don't know if they'll have two control points, or if they'll leave 151 as an intermediate for the approach to Lithonia and start the TWC there.

Regardless of the specifics, it seems their approach finally makes sense. I don't know if you're familiar with the divisions, but the Atlanta Terminal subdivision goes all the way to 149, right about where the spur to that big industrial park branches off before the yard, with the Georgia Sub being after that. So it seems they'll standardize the Atlanta Terminal to CTC with its PTC overlay, and the Georgia Sub to its APB/TWC with its PTC overlay.

Also of interest, today it was one busy little railroad! When I went by, there was a train working the north end of the yard (A752?) a train working the south end of the yard (A758), a southbound intermodal further down the siding (197?), and a northbound intermodal (198?) waiting at 135.

[SleepyCat]

Dear MattW;
Traffic is only going to get BUSIER. CSX installed an additional storage track for more tank cars, to serve its customer the asphalt refinery (I forget their name!) off Marbut Road right where the stainless steel utility box for the powered turnout is located of the Lithonia NE meet. Additionally in 2012 CSX extended one of their sidings in the Lithonia yard closer to the Maddox Road crossing, the last crossing before downtown Lithonia Main Street crossing. CSX is also installing a switch stand for a new track to serve the new recycling facility (Encore) that just opened up last year off Chapman Road. When I visited the recycling center weeks ago for the first time I asked them if they were going to make use of the rail line to haul away material. They were in the process of clearing away land for ballast and track, fulfilling their end of the installation agreement. Now if you turn onto Marbut Road from Stone Mountain Lithonia Road, cross the track while looking to your left you will see work being done in the new track installation. It means we're going to have gondolas filled with scrap in the Lithonia yard awaiting collection. Before I worked nights I would stop at the Lithonia yard in the dead of night and watch Road switchers drop off cars and gather what the locals left for them. This is a happy turn from years ago when businesses began to use more trucks than rail in Lithonia. Right now I believe the Lithonia Industrial spur serves only four customers, tops. However if you feel like traveling to Social Circle and parallel the Georgia line before Rutledge, you will find a large new business only two years old served by two new tracks of the Ga line. Downtown Madison is even better; The Squaw Creek Southern Railroad has installed a new maintenance booth across from the old Georgia line depot, where the two lines parallel each other and new crossing gates.

I agree with you that CSX is going to use PTC overlay to the APB/TWC on the Georgia line. I took pictures close-up at Scottsdale on August 7th and discovered they are replacing the old US&S searchlight signal combination box (big surprise). A stand for a new signal is located adjacent to it. But I am still curious how PTC will affect TCS between Scottsdale and Kirkwood. The TCS system allows ONE train per direction between Kirkwood and Scottsdale; this makes senses as the next meet occurs on double track near the MARTA East Lake Station (there are two sidings at Avondale but not one of them is long enough to accommodate a full length train).

SleepyCat.

[MattW]

Drove the route again today. Nothing new between Scottdale and the intermediate at 152.9, it still has its lower head turned out of service. But the intermediate at 151 (approach to north end of Lithonia) had its seaboard signal replaced with new, taller Darth Vaders. They were turned toward the tracks, but didn't appear to be in-service. The cabinet also appeared to be more permanently installed.

But inspiration hit on what 152.9 might be. I had assumed that it would be a control-point which would show restricting, red over yellow or red over lunar (I've never seen restricting shown at Lithonia, I've been assuming R/Y) but Jersey Mike actually gave the clue in one of his blog posts. Apparently, CSX likes using yellow over yellow for advance approach, so if the absolute at NE Lithonia was at stop, 151 would be approach, and 152.9 could show advance approach.

If they're working on PTC on the Georgia Subdivision, they haven't made it to Conyers yet, or at least they haven't been obvious about it. Based on the presentation you linked a number of posts ago, it doesn't seem the signals would change all that much, maybe just an antenna, the presentation isn't clear, but the switches should have an equipment box and an antenna nearby and I haven't seen any of that yet in Conyers. Speaking strictly as a railfan, I hope if they do have to do something to the signals other than just adding something inside the equipment box, that they don't "fix" the signals at the North end of Conyers (141.7). Right now, they are the only non-approach-lit signals between Scottdale and Covington (the extent of my intimate knowledge of the line) so as a railfan, I want them to stay that way!

[SleepyCat]

Dear MattW:
Like you I have not seen any more large developments of PTC on the Georgia line. I agree with your diagnosis regarding the cable outlay and equipment possibilities at the end of the Stone Mountain siding in the eastbound direction. Right now it seems like the CSX crew have done preliminary setup and are awaiting the moment to finalize installation. Beyond the milepost 151 ABS signal there is a repeater for the track pulse code system located near the defunct Coffee Road grade crossing and after that the interlocking at Marbut road. The CSX crewman said ‘they were beginning with milepost 151 and working their way back to Atlanta’; as you said this is the Atlanta terminal. CSX's approach of taking care of Atlanta first makes the most sense when you consider that PTC overlay between 151 and the rest of the line should be simpler. Junctions complicate PTC overlay just like the one at Kirkwood near Eastlake MARTA station, where the Georgia line meets the Abbeville (Athens) subdivision. The last junction on the Georgia Line before Social Circle that I am aware of is the ex-Great Walton located behind Bojangles restaurant on Highway 278 in Covington. It is unique that there are two flowerpot ABS signals, one before and one after. They also accommodate the storage siding. Concerning overall signaling presently on the line I decided to contact Carsten Lundtsen, the fellow whose webpage hyperlink I provided earlier on ABS and Interlocking’s. I was kind of curious as to the exact nature of interlocking’s on the Georgia line as they are spaced quite a distance apart at least twenty miles (Lithonia, Social Circle, and Buckhead) and using local powered turnouts. This is what Mr. Lundtsen had to say;

“Vincent, from your description (I don't know that particular line) it sounds like the line is APB with some (or all) sidings equipped with automatic interlockings. I've seen similar on the BNSF (in dark territory though) but it is a way to semi automate sidings without implementing CTC islands. Nowadays sidings like that are often equipped with radio controlled switches instead which is probably cheaper. The automatic interlockings are usually designed to automatically clear signals past the siding on the main but if a train pulls up by the switch and operates a button or key it can line itself into the siding. It can later also line itself out again. Usually the term "automatic interlocked" is used for the interlockers controlling at-grade crossings of lines, but any kind of interlocking that isn't dispatcher/operator controlled is an automatic interlocker.

Carsten Lundsten
Solrød Strand, Denmark


Den 20-08-2014 20:16, Vincent Kelly:
Dear Carsten;
I have a question not covered under Interlocking and TCS/CTC basics. The CSX Georgia Line subdivision that goes by my house utilizes a combination of Track Warrant and ABS. The line is mostly single track and interlocking’s for train meets are spaced 20 miles apart with turnouts controlled by a power switch activated by a key inserted into a compartment on the signal at the interlocking. The turnout will allow a train to enter a siding before returning to its original position after the last car. I think the ABS system is actually APB as described by one of the crew because the interlocking signals are always in the most restrictive element (red) albeit with an approach-lit feature until an oncoming train triggers green indication when there is no opposing traffic. However it will maintain red position when there is opposing traffic well beyond the siding on the mainline. Can you describe what kind of system this is and the terminology for the local powered turnouts? I heard one CSX engineer refer to them as Partial regenerative or, Restorative.

I forgot to inform Mr. Lundsten that the Georgia line is Dark Territory.
As I see more developments I will keep you posted. I find this revitalization of the line highly intriguing. For years the Georgia Line has been ‘the red head stepchild’ of CSX. I believe things will really begin to be different when and if Norfolk Southern re-installs some kind of control signaling on their reserve ‘S’ Line between Atlanta and Macon. The line once had CTC, but because it was failing and relied on old telephone poles NS downgraded it in the early 1990’s converting it to Dark Territory. Right now it only accommodates four to six trains a day but because of growing overcapacity on the NS main 'H' line between Atlanta and Macon it should be interesting to see how long NS can avoid upgrading the S. I would be willing to bet CSX wishes it had not sold the former Silver Comet line from Atlanta to Birmingham with all the new burgeoning traffic.

[MattW]

Does anyone know if they've upgraded the GA Sub's signals out ahead of this PTC install? I had read here and elsewhere that the signals weren't trusted. Under the old DTC system, I understand that some kind of clearance could be issued that would allow trains to follow each other on signals. However, I understood that that couldn't be done on the GA Sub because they didn't trust the signals. Has that changed? A while ago, I heard Q197 (Nashville to Savannah) get its clearance while it was at MP 155 for 149 to 132. So I went to the convenience store and grabbed a drink. I must have just missed it because when I saw the SB signal at the north end of Conyers, it was at approach, then came up to clear a second later. But maybe 3 minutes later, Q460, which was in the yard when 197 got its EC1, came through. The other signals are at 138.9, 135 and 132 (as far as I know), so I highly doubt Q197 had made it to 132, and released its authority. So do they let trains follow each other using the signals now? Did they do that as part of this PTC upgrade Sleepycat and I have been observing?

[MattW]

Well, CSX is continuing with the upgrade. Today, the signal at 154.4, the South end of Stone Mountain had its replacement standing next to it. Like the intermediate at 153, this one is a 3 over 2 head signal southbound, and a three-light signal northbound. CP-Scottdale (162.5) also had a new signal erected (in less than three hours to boot!) and both directions are 3 over 2. I understand this for Scottdale, but not at 153 or 154.5 unless CSX is implementing Advance Approach (Y/Y down here) on its intermediates even though signal blocks here are already approximately 2 miles long