We have probably covered this before, but what are examples of busy single track lines? I was reading the thread on Edlestein and it was mentioned there are about 8-10 trains on that line and there are capacity issues.
I understand there are a number of factors that affect the capacity of a line such as speed limits, yards, signalling, type of train control (warrents, CTC, etc), grade, curvature, etc.
What are examples of single line tracks…and by the way, how do you define single line track (more on that later)?
As for me locally, the NS (ex NKP) Chicago - Fort Wayne line typically sees 25-30 trains per day. It is single track, CTC, with sidings about every 7-10 miles.
On the other hand, the CN (ex GTW) line from Toronto to Chicago is double track except for about a 8-10 mile section from Sedley to Lincoln (Valparaiso). It typically sees 30 - 35 trains per day. I understand that small section is single track, but would one consider it as a single track line? I wouldnt.
Other busy single track lines I can think of include:
UP - ex MoPac (Chicago and Eastern Ill) from Woodlawn Junction down to Findlay and then on to Salem.
CN - ex IC mainline from Chicago south.
NS - ex Wabash line from Detroit to Decatur
CSX -ex Conrail line from Indianapolis west to St. Louis.
I believe all of these are CTC. What factors come into play on these or other lines?
As you point out there’s a gray area between a “mostly double-track” and a “mostly single-track” line. There’s no right or wrong answer to that one, but generally speaking the line will be called “double-track” even if it has a short single-track section, such as over a bridge, so long as the single-track portion doesn’t become the determinant of the line’s capacity. For example, the Santa Fe main line from Chicago to Kansas City is always (in my experience) referred to as double-track, but it does have a single-track bridge over the Missouri River at Sibley, Missouri. On the opposite side of the coin is Union Pacific’s Oregon Short Line from Granger, Wyoming, to Pocatello, Idaho, which no one would call double-track even though it has a good-sized chunk of double-track from McCammon to Pocatello.
The following is a major digression:
Of note, double-track and two main track are not quite the same thing – “double-track” is the term for two tracks that are restricted to directional running under the old Rule 251 (as in “251 Territory”) whereas the term “two main tracks” is used for two tracks where trains can run in either direction on either track. This is a method-of-operation distinction that means a lot to those of us who come from the operating or signaling departments. Unfortunately the latest revision to GCOR muddled this. 251 Territory is almost always signaled but there are a few examples of significant runs of dark double track, such as the joint C&S-D&RGW (now BNSF-UP) between Southern Jct. (Pueblo) and Walsenburg Jct., Colo., about 50 miles. Two main tracks almost by definition is CTC; there might be some short examples of unsignaled two main tracks but I don’t know of them. There was at least one significant length of ABS bi-directional signaling, the D&RGW from Helper to Kyune, Utah. I’ve never heard of another one though there might have been. In all cases – 251 and CTC – trains proceed on signal in
I was hoping you would jump in on this…thanks for the quick reply. I certainly understand your distinction between double track and two main tracks. Back in the day I would spend time at Effingham and would often see the IC run against the traffic. The operator would pass up orders, or perhaps clearance for that.
I completely forgot about the Santa Fe main out in Kansas - Texas. That certainly is a major stretch of busy single track railroad. I am not sure what status they have achieved in converting to two mains, but it will certainly make life a bit easier.
The whole capacity issue is very interesting to me, as is the economics of utilization of those assets. No doubt there is very spirited debates between operation departements and finance folks regarding investments and the returns on investment.
Which is worse…a stretch of railroad which has too much traffic (not enough capacity) or a line which is under utilized? Probably depends on whether you are running the division or running the company and what your bonus is tied to. Comments?
The Sunset Route is lot less single-track than that. The high-volume section is West Colton, Calif., to El Paso, Texas, 767 miles, which has 365 miles of two main track or double track. East of El Paso the Sunset is indeed almost all single-track to Houston, but the traffic is much lighter there.
If I said anything about double track on the thread about Edelstein, I apologize. I certainly know the difference between double track and two main tracks.
The UP line south from Nelson is single-track, TWC, with no block signals (except on the previously-mentioned stretch near Pioneer). CTC with existing sidings might help, but not nearly as much as CTC with added second track in places. If (a big “if”) the track is maintained for 49 m.p.h. now (the timetable and general orders keep changing it from 49 to 40 and back again), the addition of signals would probably up that by 10 m.p.h. with little else done to it.
As of 10 November BNSF says it has only 51 miles of the 2,203-mile Transcon that remain single-track, and plans to complete the second main track by mid-2008. Presumably the Sibley Bridge will remain single-track; at least I have heard of no plans for a second bridge there.
I think the underutilized plant is far worse from everyone’s point of view at a railroad. An overloaded track represents opportunity to increase revenue and profit, and add capacity. An underutilized plant is just stranded investment.
I doubt in this case that the lack of signals are the limiting factor on maximum authorized track speed – the restriction to 40 mph sounds more like track quality (Class 3 vs. Class 4, which are 40 and 60 mph maximum for freight, respectively). Lengthening sidings until they’re long enough to hold the longest trains commonly operated, decreasing the distance between sidings, and elimination of slow orders, will do much more to increase capacity than merely the addition of CTC. There’s nothing “wrong” with single track with long sidings, and if it’s operated and maintained properly the need for a second main track (except on long grades and in terminal areas) shouldn’t kick in until train count gets upward of 50 per day. (I’m speaking of a freight-only operation, not mixed freight-commuter or freight-corridor passenger).
I always found the BNSF Beardstown line an interesting operation.
It is primarily single track with TW’s, but a couple of stretches of CTC. There are quite a few coal trains on the line. I believe they are experimenting with a GPS system on that line.
Anyway, the interesting thing about that line which I discovered was as a train left a siding, it left the siding open, which meant that the next train would have to stop and close the siding. Obviously, that makes sense as a conductor walking well over a mile after closing the siding would be pretty inefficient. Not being all that familar with track warrents, there must be a line in there for the next train to proceed to the point of the open switch and then close it.
Carl, you made no mention of the Nelson line being double tracked, the discussion of that line triggered a thought, similar to the smell of baking bread triggering my hunger.
Never saw much traffic on that line when I was regularly travelling out that way in the 90’s. Is there a Alton Southern to Proviso train still on that line?
Down at Springfield, they use the C&IM line to access that line from the G&MO line. Ridgely Tower, as I understand it, is still open!
1)) Another delay in meets on some subdivisions are level crossings, holding back the train to prevent blocking auto traffic and even cutting the train up while waiting. 2)) Another way to improve meets is to have track speed sidings. When sidings are a mile and a half long with an equal length train taking the siding at 10mph , that adds up to 3 miles of slow speed. These two points affect the capacity of a single track line.
Scheduling looks like one of the bigger problems on that old wabash main, I’m sure someone will point it out if I’m wrong, but do railroads even try to make regular shedule runs anymore?
Seems like it’s either feast or famine on the NS Huntington district, there will be hours that go by without a single train, then all of a sudden it’s eastbounds vying with westbounds for clearance…seems like NS could massage some of the kinks out of the conflict simply by making better use of the 24 hours in everyday, probably easier said than done.
My guess would be that whoever controls the traffic on that line probably looks at the instances of peak conflict between movements, and says the line is worked beyond reasonable capacity, while not really noticing the hours in between, where the rails lay empty.
I guess that “limiting segments” have a lot to do with that?
Earlier in the year I took a trip west on what is normally a sleepy Saturday, and the line was hardly in use through Huntington, Wabash, or Logansport, but between Clymers and Lafayette, all I saw was trains on that track.
In fact coming back from Lafayette was a tad humorous, I passed a total of 4 eastbound trains all sitting in sidings waiting for some west bound train to come along, the first one or two didn’t really surprise me but after encountering #3 and #4 It really occured to me just how backed up that line was. Which, when the westbound finally came along, looked like a local it was so short… Mybe he was just taking advantage of a gap that was working in his favor, and the real priority tying everyone up was still coming.
Seems like a little forward planning would avoid much of the conflict.
I believe the manifest we send out that way from Proviso is MPRPB (to Pine Bluff, Arkansas). The train in the other direction is MASPR. IIRC, MPRAS/MNLPR is the pair that runs via Yard Center. There was a brief time in CNW history that we sent three manifests from Proviso at least as far as Peoria (and one more from Clinton).
BNSF has used the Beardstown Sub to do the FRA-required prototype testing for its Electronic Train Management System (ETMS), which is a Wabtec-designed and manufactured Communications-Based Train-Control System overlay – that is, it provides train-management and safety improvement by enforcing speed restrictions and authority limits, but it is not a train-control system. It does use GPS along with several other data streams to determine train speed, location, and direction (I want to emphasize that GPS is just one of the data inputs, not the only data input).
Yes, in hand-throw switch territory in TWC or DTC operation, with no cabooses, in practice there will almost always be a switch left open after a train meet, and the dispatcher protects the open switch. See GCOR 8.3 Main Track Switches.
The use of “double track” meaning directional (current of traffic) and “two main tracks” meaning trains running in either direction on either track was not universal.
In the Rock Island and Missouri Pacific employee timetables both of which, along with the Katy and the Cotton Belt, used the Uniform Code of Operating Rules., multiple main tracks regardless of how used, were listed as two main tracks, or where applicable, two or more main tracks. The method of operation on two (or more) tracks was provided in the special instructions, or in the stations column. BTW, in the UCOR, movement by signal indication in the same direction (current of traffic) were Rules 450 to 453. Movement by signal indication in either direction on the same track (CTC) were Rules 400 to 406.
Unless the leaving switch is a spring switch. Some railroads do have a specific line to protect the open switch. Others use the “Other specific instructions” line.
Agreed! There are few things more irritating than a long siding with a grade crossing through it that can’t be blocked. Then the first-to-arrive train has to hold off the crossing and the meet will take a long time.
The effective track speed of a siding is affected by the turnout size, presence of signaling, available signaling aspects, whether the siding is bonded or non-bonded, track condition in the siding, and the position of the switch at the other end of the siding. #14 or #15 turnouts are good for 30 mph and if the siding is bonded it can be signaled for a better than lunar aspect. But so what? It’s all well and good to put in a #20 turnout and signal a siding for 40 mph operation, but if the train is going to come to a halt at the other end of the siding it is going to drag in regardless. Theoretically if you build really long sidings allow you to make non-stop meets, reducing the time spent in the control point by the train entering the siding, but in practice the timing rarely works out and one of the trains must stop and wait on the other. In practice there’s not much or a benefit to something better than the 8,000 to 10,000-foot bonded siding with #14 or #15 turnouts and at least a red over yellow aspect to enter, until you go all the way to a siding that’s really a second main track of at least 5 miles in length, with #20 or #24 turnouts.
As well as DTMF switches, but these are both considered under separate rules than 8.3. There’s also variable and automatic switches, but I’ve rarely seen these outside of terminal areas.
I know the trackmen and signal maintainers don’t like spring switches very much but from an operating department point of view I find them quite effective.
Thanks once again. Could you please explain “bonded”.
I would think the sidings with road crossings would be a very big problem. There are a couple in this area on the NS NKP line that are rural. Often they will simply not cut the train. No doubt the attitude is that rural roads are generally every 1 mile. Let the driver go an extra mile.
Can someone clarify the IC’s sidings in Illinois? I seem to recall reading at one time when they converted from double to single/CTC that the sidings were pretty long, but had no intermediate signals.
So…what exactly is the situation when entering a siding on a “diverging approach” signal (red/yellow). One must be prepared to stop at the next signal. Does that restrict the speed within the siding? If you do have the 3 mile siding, what governs the 10mph running?
“Bonded” is railroad slang for “equipped with a track circuit.” It comes from the rail bonds that are required to electrically connect jointed rail. And until fairly recently, virtually all sidings were jointed rail. A bonded siding can be entered on a signal better than a lunar aspect whereas the best possible aspect for a non-bonded siding is lunar.
Here’s why. A block signal has two possible functions, it advises of track conditions ahead, and, if and only if it is an absolute signal, it also grants authority to proceed. A signal at an end-of-siding turnout in CTC territory is an absolute signal (with rare exception), and thus grants authority to proceed over the turnout on the route (if there’s more than one available) and/or speed specified by the signal indication. Because a non-bonded siding has no track circuit, the signal system has no information about the condition of the track ahead – for instance whether there’s a broken rail, or the siding is already occupied by a train. Therefore the signal entering a non-bonded siding only grants authority to enter the siding and thus the maximum authorized speed of the train entering the siding is restricted speed (20 mph max, able to stop in half the limit of vision, etc.). A lunar signal is commonly the one used to indicate Proceed at Restricted Speed.
You also need to have a signal verifying that the switch is lined and locked for the direction of movement otherwise there’s not much point to having a power switch. This is done by creating a track circuit through the “O.S.” itself (the track between the signals and over the turnout is called the O.S.), and the O.S. has a circuit even if the siding is non-bonded.
Back in the old days a lot of railroads that installed CTC didn’t have infinite budgets to do so – CTC being quite expensive – and thus did not bond the sidings. Also, since much of the time a train entering a siding is going to stop at the other end