New NORAC Signal Rules!

Yes, and before people get all nit picky yes NORAC is indeed adopting both new rules and a couple new aspects that go along with old rules.  All of the new changes have in fact been used for many years by a number of member railroads as system special instructions and moreover they have also been seen in other railroad signaling systems.  This is a nice example of a signal rules committee looking at the state of the art and deciding not to keep its head buried in the ground.

The new rules were made effective in the 11th edition of the NORAC Rule book released on Feburary 1, 2018. I've been a bit busy since the start of the year so I just hadn't noticed until now XD

We begin with Rule 281a, Cab Speed, which has been modified to include SEPTA's *G*/*G* dwarf indication which it has been using for about the last 10 years.  Also included was a PRR pedestal indication probably because of some situation on Amtrak.

 The next change plugs a major hole in several eastern signal aspect systems in that there is often no Approach indication available on dwarf signals. Y/R is Slow Approach, Y is restricting and for years NORAC had to make up with displaying Y/*R* Medium Approach for straight routes.  However there was one obvious solution and after appearing on the Conrail SAA timetable as a special instruction for years, *Y*/R has been adopted as Approach.  CSX please take notice.

A bit more consequential is the long overdue adoption of Medium Approach Slow.  Unlike CSX which had reserved R/Y/G for M-A-S forcing R/Y/*G* for M-A-M, NORAC went with a nod to the PRR using R/Y/Y.  This aspect had long been used in by the MBTA in the Boston area and possibly also on the former Boston and Maine territory. More recently it had been incorporated into Caltrains new speed signaling system in 2003. Note, NORAC Rule 283b does not include the "when first becomes visible" admonition, which I would suspect is something they are trying to get away from.

Finally in a weird nod to the Seaboard Coast Line, NORAC has adopted Limited Approach  signal as Rule 286a.  However, unlike the CSX Rulebook which is a bit ambiguous about when a train must slow to Medium Speed, NORAC Rule 286a states that Limited Speed applies only through the switches and turnouts, then Medium Speed applies.  Like Rule 286 Medium Approach, trains must begin reduction to Limited Speed as soon as it becomes visible.  I suspect this might be used to claw back a few seconds where trains had previously been stuck at Medium Speed due to a far-yet-visible Medium Approach indication.

All in all these are sensible moved by NORAC.  The real question continues to be when CSX will finally adopt *Y* Advance Approach!!

Better Know a Signaling System - Delaware and Hudson

Here in the inaugural episode of Better Know a Signaling System I am starting with something small to just sort of see how things go.  Actually brevity that is one of the interesting features of the old D&H signal set with only 10 total signal rules in their 1948 rulebook or 9 if you go by this undated chart that appears on railroadsignals.us

While 9 or 10 signal rules might sound like a lot compared to the 21 or seen in under NORAC or CSX, the D&H finds itself in good company with many other railroads not operating multi track main lines in and around busy urban terminals, especially those making use of route signaling.  The D&H is a very conventional speed signaling system designed for single main track operation with passing sidings.  If you remember back to my signaling dialects post you'll see that the D&H uses Y/Y for advance approach, R/Y/G for Medium Approach Medium, R/Y/R for Medium Approach and R/Y or R/R/Y for Restricting.  The R/Y/G Medium Approach Medium was made possible because the D&H made a point to use high signals at siding exits and R/Y/R Medium Approach was enabled by using only three headed signals at interlockings.  Here is an example of the three head policy that was still in effect up through about 2011 with brand new Unilens tri-heads installed on the former D&H Colonie Branch at CPO-5.

Unfortunately since CP went all Darth Crazy, two head signals are now being allowed to slip through as seen here at CPF-478.  Hmmm, looks like they are dumping right handed placement as well.

Contrast with the Boston and Maine's CPF-464 right across the Hudson River which has no problem making use of two headed signals and R/*Y* Medium Approach.

Another interesting practice that comes across on the 1948 signal chart is the use of offset heads for automatic signals.  A common practice back in the day, but one that is still followed in Canada to mark automatics instead of number plates.  It is not surprising that under CP ownership this practice was not challenged.  Although not a new CP install here is the MP 8.2 automatic on the Colonie Branch with the offset heads.

Staying with the 1948 chart we find a few interesting tidbits when it comes to dwarves.  Without slow speed indications the D&H could use G/R for clear and Y/R for Approach.  R/*Y* was used for Medium Approach to make room for R/Y Restricting.  The most interesting dwarf was Y/G for Medium Approach Medium, which I guess came up more than Approach Medium.  Single head dwarfs were limited to Y and R/Y Restricting and R Stop.  So kudos to the D&H for not installing Slow Speed turnouts I guess.

Aside from its dwarfs the only non-NORACy indication the D&H adopted was the Y/Y Advance Approach.  Of course with no slow speed signals it makes perfect sense.  There was also a R/Y/Y Medium Advance Approach, which was left off the Railroadsignals.us chart.  The thing is that when the Guildford Rail System (ex-B&M) purchased the D&H in the 1980's it did more than re-mile the main line from Binghamton to Maine.  In the 2007 CP Northeast US Timetable (towards the end) we can see that the signaling has gotten a lot more...conventional.  There is suddenly a R/R/G and dwarf G Slow Clear along with dwarf *Y* Slow App.  To compliment those Y/Y is now Approach Slow and *Y* picks up Advance Approach.  All the other old dwarfs are just plain gone except for Y/G, which is now Approach Medium.

So that's the story of the D&H signaling system.  It started out pretty conventional and then got even more-so after several new owners put their hand in the pie.

CSX: Where TWC and DTC Collide

Like most North American Class 1 railroads CSX is an amalgamation of various predecessors. Not only are there the Seaboard and Chessie System components (themselves the result of mergers), but the former Conrail and Louisville and Nashville territories and several smaller lines such as the Rechmond, Fredericksburg and Potomac and Monon. Each were incorporated with their own rulebooks and signaling practices and until recently CSX continued to maintain multiple rulebooks across its network. In 2007 CSX switched to a brand new unified rulebook, but in order to avoid any drastic change in operating practices many of the previous flavours of rules were simply combined into a single document. Apart from the signal rules (which have sections for Chessie, Conrail and Seaboard aspect systems) the section which most heavily reflects this sort of conglomeration is the one concerning Track Warrant Control (section 5, page 9, if you want to follow along.)

Before the Conrail merger in 1999 CSX used Direct traffic control on all of its unsignaled lines. DTC makes use of fixed blocks with movement authority provided from the dispatcher to the train directly via radio communications (hence the D in DTC). This was in contrast to previous systems where trains would follow a predetermined timetable and any changes would have to be given to crews via block operators or lineside telephones (aka Indirect Traffic Control). When Conrail trritory was incorporated those lines used the Form D Control System or DCS. This was similar to DTC it referenced stations and interlockings as valid block limits (with a block limit sign being a form of station), but don't let the D in DCS fool you as DCS is a Track Warrant system, not a DTC system.  Track Warrant Control not only allows for movement authorities to be given between traditional block limits, but also to any whole milepost or switch.  Moreover Track Warrants can be used for other things besides train movement authority and usually end up combining several forms, like speed restriction updates, into one. While in theory this could have just meant a change in paperwork, mucking about with safety critical systems takes care so CSX decided to make the new TWC system backwards compatible with the old and therefore split it's new TWC rules int two sub-sections TWC-DTC and TWC-DCS to accommodate the differences between the original DTC and DCS systems.

While TWC is more versatile, DTC is simpler and more efficient at doing the things it does.  Instead of trains needing to write out new or amended track warrants, DTC blocks cab be released as they are cleared and then immediately given to other trains. Still, it is clear that CSX's preference lays with the TWC-DCS rules as they immediately went about ripping out all of the old DTC block signs wherever it was most practical like on signaled main lines where DTC used to substitute during signal outages.  DTC references were also largely removed from the employee timetables indicating that the sign removal wasn't just a cosmetic change.  Still, there remain a few locations where DTC remains in effect, mostly on unsignaled secondary lines where use of DTC is more efficient than having crews fill out full Form D's.

Say Goodbye to old CSX DTC Block Signs Like These

Where DTC will be most difficult to dislodge is in the circumstance of bi-directional ABS without traffic control, known under NS as Rule 271 or out west as TWC-ABS.  One might see bi-directional automatic block signals as an indication that a line as been equipped with CTC. However as spelled out in its name, CTC is a system for Traffic Control, not block separation. Traffic control means that when a train is given a route into CTC territory a flow of traffic is established such that opposing movements are not permitted to enter that line. Failure to establish a flow of traffic can result in Mexican standoffs away from passing points or certain race conditions that can cause a head on colision. Because CTC requires logic beyond simple automatic block occupancy to establish a traffic flow back in the day it was more than some lines wanted to deal with. However the advantages of ABS with its broken rail, hand switch point detection and flexibility for following movements could not be ignored. While not common on CSX it does appear occasionally, with the former Monon Railroad main line being perhaps the best known example with the line retaining the same system of operation even after the semaphores were removed.  The new system, known as TWC-DTC (ABS) (!) is at least slightly more clear than the old Rule "120-132 (243-246)" label. 

To accommodate both its traditional and signaled flavors, there are several types of DTC block authorities that can be given. The first is Absolute Block, which has the standard definition, but allows trains with such authority free use of the block in both directions. The next is Clear Block. This grants authority in a single direction guaranteeing the block free of obstructions, but allows say a train in a siding to proceed in the opposite direction on its own DTC authority once passed by the conflicting movement. The third is Occupied Block, which like the name implies allows a train into a block with an obstruction. This is not intended to be used for permissive operation, only the case where one train needs to assist another or pickup equipment left unattended on the tracks. Finally there is a fourth type of DTC permission, Proceed Block. This grants trains the authority to proceed governed by fixed signal indication. This is the only type of authority given in TWC-DTC (ABS) blocks and this rule unlocked the mystery of why such a system exists in the first place back when I first encountered it several years ago.  While all other railroads use full length Track Warrants on bi-directional ABS territory CSX has allowed this situation to remain the province of DTC even as DTC is abandoned elsewhere. 

How to Patch Your Signaling System (in 3D)

In this week's installment I will travel to Georgia to highlight an interesting development on the CSX Abbeville Subdivision that I discovered while visiting a friend last year and how it ties in with a pet peeve of mine that wound up influencing signaling in the UK. The Abbeville Sub was a former Seaboard Air Line route between Atlanta and the port city of Wilmington, North Carolina. The line is your typical single track CTC with passing sidings and sees only freight traffic including double stack trains.

I have mentioned before that the current practice in North America regarding signaling system alterations is to typically replace the existing signaling even if the existing signaling if relatively new with solid state components. My suspicion is that it is easier to test new signals in situ than to try to patch in new vital logic to the older, in service equipment. However every so often there are exceptions to this rule, usually where a single signal is replaced due to structural deficiency or damage. Less frequently single signals will be replaced as part of a change in the physical plant. (And least frequently will the old hardware be modified.) This post is an example of CSX performing a simple signaling upgrade and only replacing the signals that were directly affected instead of everything in sight.

The location in question is between milepost 506.8 and 513.4 near Athens GA. The upgrade in question was the installation of a new interlocking at milepost 509.6 to serve a large grain customer so that crews no longer had to operate a hand throw switch. Previously there had been an automatic signal at 510.1, an interlocking at the south end of the Fowler Junction controlled siding and another interlocking at the north end of the siding. The distances involved were 2.3 miles between the auto and SE Fowler and 9,800 feet between SE Fowler and NE Fowler. All signaling was of Seaboard origin and dated from the 1970's or early 1980s. On CSX a controlled siding is one with interlocked end points, but no train detection so all diverging moves into the siding receive a Restricting aspect. Signal progression for a Restricting signal on CSX is just Approach to Restricting so the 511 automatic could make do with a single 3-lamp head in each direction. However the new interlocking at milepost 509.6 would split the 2.3 mile long block into two blocks of 1.5 and 0.8 miles respectively. While a 1.5 mile block wasn't a big deal, the 0.8 mile block would be too short for a train to safely stop and it was decided to install 4 block signaling on either side of the short signal block. This would require the signals at the 513 auto, the 511 auto and NE Fowler Jct to display an Advance Approach aspect, which they were not set up to do.

Now had this been working under NORAC, Union Pacific or Canadian signal rules the change would have been trivial because Advance Approach (preceed prepared to stop at second signal) is represented by a flashing yellow (*Y*). However CSX's Seaboard System rules use Y/Y for Advance Approach. This means a hardware modification to install a second head or, completely new signals and that is what the signal vendor encouraged CSX to do. So here we see the new 5110 automatic signal that I happened to catch displaying Advance Approach. Note the old (P) board at the base of the signal which was used in the Seaboard system to mark Permissive automatic signals as opposed to the more common numberplate.

I was pretty lucky to catch the 511 auto displaying Advance Approach as the signal itself is approach lit providing only a brief window of time when a train is in the block where one can catch anything lit up. Aside from the actual signal hardware everything else about the TCB signaling in the area had been left unchanged including the relay cabinet and the original concrete signal base that the new mast appeared to be glued on top of.

This is a good opportunity to explain why I dislike the Y/Y advance approach indication.  The obvious problem which is demonstrated by this complex patch job is that you have to add an additional lamp or signal head when shortening block lengths instead of just setting the yellow to flash.However from a signaling theory point of view Y/Y Advance Approach makes the signal aspects much less consistent. Basic block type signals can no longer all be displayed on one head (or with one lamp). Moreover on CSX Y/Y for Advance Approach displaces what would normally be Approach Slow into a three lamp aspect, Y/R/G. This then serves to dilute the impact of having only absolute signals three lamps as well as disrupting the pattern of the "Approach Speed" series of signals listed below.

Y/R = Approach Stop
Y/L = Approach Restricting
Y/Y = Approach Slow
Y.G = Approach Medium
Y/*G* = Approach Limited

By stealing Y/Y for advance approach the pattern is disrupted. Y/Y was originally the standard way to display Advance Approach and was actually copied by the Big 4 British railways when that system adopted color light signaling in the 1930's.  The reason for this was because at the time flashing relays were both expensive and unreliable, but as technology marched on flashing signals became common and when Conrail was forming what would become NORAC in the 1970's the decision was made to dump Y/Y Advance Approach and replace it with flashing yellows.  The real headscratcher is that even if CSX's embrace of Y/Y advance approach precluded wholesale conversion to the two headed style of Approach Speed signals, the Seaboard rules do not currently make use of *Y* for another indication.  Much like Conrail did CSX has been free to phase it in ever since it embarked on its massive re-signaling spree starting around 1999.

Anyway, in addition to the 511 Auto the 513 Auto also needed replacement to fit Advance Approach due to the now "short" 1.5 mile block between the 511 auto and the new interlocking.  Again had *Y* been available all the original signaling hardware would have been able to be left in place.

Speed Signaling with Caltrain

Between 2002 and 2004 the Caltrain commuter route on the peninsula between San Francisco and San Jose underwent a near total rebuild to bring it up to the same high tech standards as many of the companies that had their headquarters adjacent to its tracks. At the turn of the 21st century the line was operating much as it would have been at the turn of the 20th with basic single-direction Automatic Block Signal operation with hand operated crossovers at temporary block stations where orders would have hooped up to trains during single line working. Much of the line still used jointed rail and there were only five interlockings on the entire route clustered at the north end near San Francisco, one of which was the 4th and King St terminal and the three of the remainder being used by freight trains accessing spur tracks.

Fortunately for history the line was documented by a West Coast signal fan and you can see his work here.

http://www.redoveryellow.com/signals/coast/_C326-359.html
http://www.redoveryellow.com/signals/coast/_C360-381.html

Two years later the line could not be more different. It was upgraded to fully bi-directional CTC operation with welded rail and large sections with concrete ties. Stations were rebuilt and two long 4-track passing sections were constructed near the Northern and Southern portions of the line to allow new express train services to pass locals without delay. A plethora of new interlockings were installed to allow 2-track express passing or just easy recovery from engineering works. Again, all of these changes were documented by the same signal fan.

http://www.redoveryellow.com/signals/coast/after_ctx/_C326_358.html
http://www.redoveryellow.com/signals/coast/after_ctx/_C359-381.html

What is perhaps more interesting is that as Caltrain owned the tracks between CP-COAST and San Francisco it was free to make the decision to abandon the old Southern Pacific inherited 'route' signal rules and adopt more modern speed signal rules comparable to those seen in the east. As Amtrak had the long term contract to run the Caltrain services this better fit its operating practices elsewhere in the country.

The old route style signaling had been popular back when interlockings were few and far between and traffic densities light, but with increased routes and higher speed differentials Caltrain dumped the whole route concept and adopted a speed signaling scheme influenced by prior art, but with its own unique flavour.

The Caltrain signal rules can be found its the following rulebook documents. Also included are the Union Pacific route signaling rules still in service on the UP owned portions of track so you can compare and contrast.

Caltrain ETT No 2
Caltrain ETT No 2 Supplement No 4

So what is interesting is that Caltrain started with the typical "Northeast" style signal set with Y/Y as Approach Slow and *Y* as Advance Approach, but dumped the use of "bottom yellow" in Restricting signals, using *R* instead. With bottom yellows now free R/Y and R/R/Y could be tasked to Medium and Slow Approach. The system retains some Western influences with the Approach Restricting aspect and Caltrain also added some innovative new aspects such as R/*Y* as Limited Advance Approach, R/R/*Y* as Slow Advance Approach and R/Y/*R* as Medium Approach Restricting. They also logically extended the Northeast style system by using R/Y/Y as Medium Approach Slow.

Because no automatic signal aspect requires 3 heads (a problem caused by using Y/R/G for Approach Slow) Caltrain was able to adopt a uniform visual aesthetic for its signals (probably to the delight of its vendor, US&S) by fitting all standard block signals with 1 head, distant signals with 2 heads and interlocking signals with 3 heads. Each head in turn was fitted with all three lamps, if they were needed or not. This gives the engineer an easy way of identifying what sort of signal they are facing, even if it means Caltrain spent a lot more outfitting signal lamps that would never need to be illuminated. On some of the 4+ track home signal gantries this can lead to quite the interesting Christmas Tree effect, especially when flashing aspects are involved.

This brings us to our main feature. Back in March I was out in the Bay Area for a conference and I was able to capture video from the north-facing railfan window of a gallery car of the entire line. Now this consists of about 40 minutes worth of video showing nothing but Clear signals and is probably something you don't really need to see, however I later filmed a second partial run at night where my express train takes the Bayshore passing route for some reason which shows off some aspects other than Clear. Also in evidence are the numerous grade crossings (including pedestrian grade crossings at stations which the trains have to whistle for) and this really cool Southern Pacific era 8-track signal gantry that was fitted with new signals and left in place. In that same area you can also see the last hand operated crossovers on the line used by local freight trains to switch between goods sidings that straddle the main line.

The first video between Millbrae and Bayshore can be seen here:





There is a gap between the way caused by my camera batteries running out.

In the second video you can see the new Lunar White marker lights that were attached to the signals in the terminal area for some reason. The terminal is the only un-resignaled portion of the line retaining its original Southern Pacific searchlights and pneumatic point machines (possibly the only pneumatic points west of Kansas City) and the Lunar Markers may be to differentiate the special case terminal signals with the new speed signaling system.

Anyway, I hope you all enjoy the video and see that converting to Speed Signaling is an achievable goal.