The Last N&W CPL Dwarfs?

It's sometimes easy to forget that the PRR position light dwarf signal was also used by PRR ally Norfolk and Western Railway in addition to the regularly sized position lights. Their PL dwarf was even included in the 1959 N&W program to partly colorize their signals resulting in something that gave off definite UK "ground signal" vibes, albeit with the ability to display green.

Although the old N&W has been ravaged by re-signaling projects over the last decade, there are still a number of well preserved lines deep in the Appalachian coal country and Virginia. However the same cannot be said for the N&W CPL dwarf as the N&W had color light dwarf alternatives in its rulebook as early as 1961. Therefore the N&W had a multi-decade head start on replacing its PL dwarfs at the point where NS started to get involved. As of the time of this post, it has been reported that there are only 4 N&W PL dwarf signals remaining in active service at three locations. The first location is Iaeger, WV, the second Coeburn, VA and the third, with two CPL dwarfs, is Cloverdale, VA.

The Iaeger example is immediately adjacent to state route 80 just east of the Tug Fork bridge at IAEGER interlocking, just past the west end of Auville yard on the Pocahontas Division Dry Fork Branch near the village of Hull where the three track N&W position lit full crossover used to be.

The Cloverdale pair are located at the east end of the Cloverdale Branch on the Roanoke District's CLOVERDALE interlocking about 8 miles north of the Roanoke Terminal in Roanoke, VA. The first governs the end of a long industrial track that serves a concrete plant and the second serves as the exit signal for the Cloverdale siding. 

The final location is actually an automatic distant signal on the otherwise unsignaled Toms Creek Branch for COEBURN interlocking on the Pocahontas Division Clint Valley District. It is located just off Tate Ave, a few blocks from the VA state route 158 and the central business district. All three locations are in the vicinity of recent re-signaling efforts and can be considered highly endangered as a couple of other known examples, including another isolated automatic distant in North Carolina, were recently lost.

Of course rare signal types have always popped up before and I'm just reporting on the results of a forum discussion so if you are aware of an N&W CPL dwarf that has been missed please let me know in the comments! The first draft of this post actually missed the Coeburn dwarf so thank you Oakley for pointing it out.

Better Know a Signaling System - Seaboard

Well last time around we explored the signaling system that ate the Northeast.  Now we can explore the signaling system that is eating the signaling system that ate the Northeast. The Seaboard Coast Line railroad, itself an intermodal amalgam of the Atlantic Coast Line and Seaboard Airline, is the 'S' in CSX and the Seaboard system of signals are those which CSX has chosen to standardize on, brushing away the B&O CPLs, C&O color lights and former Conrail NORAC signals.  The reasons is not really due to any inherent superiority, but has more to do with major flaws in both the C&O and B&O systems and the company headquarters being in Jacksonville, FL and NORAC signals were not invented there.  Note I am not going to call these CSX signals because there is still little that CSX has had to do with them, unlike NORAC, which may have borrowed most of the signal rules, but still put its own stamp on them.

Unlike the other dominant signaling system in the South used by the Southern Railway, Seaboard uses speed signals and today is one of the three major codes of speed signaling code along side NORAC and CROR (Canadian signals).  It shares a lot in common with those other codes including the three head (Normal, Medium, Slow) system and Y/G for Approach Medium.  However Seaboard is defined more by its differences than its similarities.

Seaboard's most defining characteristic is its use of Lunar White and only Lunar White for restricting.  There are a few smaller route signaling systems that have this feature, but ever since the availability of *R*, no other major railroad has relied on just Lunar White. 

Back when the Seaboard adopted Lunar for Restricting, Restricting was a seldom used indication, mostly seen where there were routed leading to unsignaled track like yards.  For normal interlockings the Seaboard did not provide any capability to display a "call-on" and therefore they made do with US&S N-3 and 3-color searchlight heads.  However in modern times it is CSX's policy to provide a restricting capability on all controlled signals.  This in turn leads to the frequent use of 4-lamp signal heads, which were nearly unheard of in the area of searchlights and pre-cast color light heads. 

The use of LW for Restricting of course frees up R/Y and R/R/Y for Medium Approach and Slow Approach respectively.  R/Y/R is also used for Medium Approach and is employed by CSX in areas where conversion from non-Seaboard signaling is under way (Conrail, RF&P, P&LE, Etc) or a third signal head is provided.  Lunar white is the first of many instances where CSX management has said "my way or the highway" when its comes to incorporating the signaling ideas of others.  CSX predecessors NORAC, P&LE, RF&P and the C&O all used lower yellow Restricting, which has the advantage of not needing 4-lamp heads, but I guess the south is always right.

 Now just because one had R/Y for Medium Approach doesn't mean that R/*Y* can go unused.  CSX has decided to fill this slot with Limited Approach, which appears to violate the principle of reducing trains to Medium Speed upon passing an Approach indication



Seaboard's other fateful decision was the continued use of Y/Y advance approach, even where the aforementioned alternate speed signal systems had switched over to Y/Y for Approach Slow.  The real kicker is that CSX does not currently use the *Y* aspect, even as an alternate Advance Approach for NORAC compatibility.  This requires that all "patch jobs" require an extra signal head instead of just a flasher relay.  Now if you look closely at the 1989 CSX signal rules I posted above *Y* is listed an a Y/Y alternative, but the original Seaboard set did not include this option and CSX itself later dropped it as well for reasons unknown.

Y/Y Advance Approach on the Abbeville Sub in Bogart, GA where a new interlocking created short blocks.

Without a two lamp Approach Slow indication like Y/Y, all situations involving Slow Speed must use "three headed monsters" to display the Y/R/G flavor.

Like several other pre-NORAC railroads (and the C&O) the Seaboard used R/Y/G for Medium Approach Slow for reasons involving one block sidings that I have already explained.  However CSX chose not to update R/Y/G to the now more common Medium Approach Medium when that indication was added in the 1990s, instead flashing the lower green up "upgrade" the older indication.  If you jump ahead to 6:17 in the following video you can see a CSX medium Approach Medium leading to a R/Y Medium Approach.



In the theoretically sound Caltrain speed signaling system R/Y/Y was chosen as Medium Approach Slow as it worked off the Y/Y/R approach slow and R/Y/G Medium Approach Medium.  Without Y/Y Approach Slow or R/Y/G Medium Approach Medium, Seaboard used R/Y/Y for Medium Advance Approach.  I suspect this might be the rarest signal indication of the Seaboard set as I have yet to positively identify a high signal location where it is employed.

Note: Do not mistake C&O Medium Approach for Seaboard Medium Advance Approach as both use R/Y/Y, but the former is much more common.  C&O signals will be covered later.

Dwarf signals are fairly typical of a speed signaling system with the major exception of Y being Slow Approach instead of Restricting.  The necessity of lunar has made the 4-light Safetrain Unilens dwarf units very popular with CSX.  Here is one displaying the Y/R variety of Slow Approach.

As one might expect R/Y and R/G are Medium Approach and Medium Clear respectively, the latter being perhaps the one case where Seaboard scores a point over NORAC.   One can tell  if a Seaboard dwarf stack protects a medium or slow speed turnout based on the position of the green lamp relative to the red. R/*Y* is provided for Limited Approach, however because of Y/R/G Approach Slow, there is no dwarf version of that indication available. 

 One might expect dwarf Y/Y to be used to the fairly common Advance Approach indication, but, bafflingly is used for Medium Advance Approach.  Unlike using Medium Approach as a Substitute for the missing dwarf Approach indication, a quirk Seaboard shares with NORAC, using Medium Advance Approach would require trains to slow to medium speed first leaving Approach Medium as the short block speed control alternative.

That's pretty much all there is to the Seaboard system of signaling.  It's a solid set of speed signal aspects, but unfortunately was never able to evolve past some of the depricated practices like Y/Y Advance Approach or R/Y/G Medium Approach Slow.  It's a real shame that CSX didn't use the Conrail merger to, at the very least, (re)adopt *Y* as an alternate Advance Approach.  

Conrail's Virtual Headed Dwarfs

The concept of a signal "head" is pretty basic to the understanding of signal aspects.  Each head is capable of displaying some chunk of information and in conjunction with other heads on the same signal the entire story is told.  In the vast majority of signaling instances the signal heads are easy to identify and are distinct from one another.  From the round searchlight targets to the hooded Darth Vaders to the massive position light  assemblies, the signal head makes the "X over Y over Z" type North American signal unambiguous in its display.  The signal head concept also applies to dwarf signals and "dwarf stacks" are a well known signaling type allowing each dwarf head its own compliment of colors to display.

 Even where unit lamps are employed stacks of up to 6 units are not uncommon to create two 3 lamp heads  such as those seen here at Amtrak's COVE interlocking.

The thing is...what if you didn't feel like spending that much money on all those pesky signal heads?  A virtual signal head is where what would normally act as a single signal head instead serves as 2 or more using the relative placement of lights without the associated spacial placement.  This is generally seen as being a rather severe form of cost cutting and is rare even in North America where signaling hardware is already fairly austere.  One of the more prominent main line examples is on the former Milwaukee Road main line between  Milwaukee and St. Paul, now operated by CP and uses 4-lamp masts to display the full range of weak route signal indications like Y/Y, R/G and R/Y.

Or a 5-lamp mast at interlockings where both Y/Y and L aspects are required.

 However the cost effective signaling award might just belong to Conrail for its use of virtual headed 2, 3 and 4 lamp dwarf signals.  Now this might be more widespread and I'm probably being a bit unfair picking on Conrail, but on the other hand the NORAC signal aspect system was tweaked specifically for just this sort of low cost signaling so I suspect that Conrail was one of the more aggressive users of the practice.  How does NORAC cater to the use of Virtual Heads in dwarf signals you ask?  G/*R* for Medium Clear and Y/*R* for Medium Approach avoids having aspects like R/G or R/*Y* create conflicts with a virtual head system.  All NORAC dwarf indications can be displayed on a signal with Red on the bottom.

Y/*R* Medium Clear at CP-TRENT  Yes, its flashing.

Why would Conrail care so much when it didn't seem to bother other railroads?  First of all there was a lot of Rule 251 double track in the Conrail territory and chronically short on cash the road had to cut itself into profitability.  This meant that when making new interlockings for single track or even double track CTC a dwarf was a better deal than a mast.  While route signaled roads out west could get by with having a single lamp dwarf display full blown Clear off a signingor reverse signaled route, Conrail's speed signaling system really couldn't.  Single searchlight or position light dwarfs limited turnouts to slow speeds so virtual head dwarfs could eliminate the problem for the same price.



Conrail went crazy with the concept.  A 2-lamp dwarf displaying only Stop, Restricting or Slow Approach could now display Medium Approach.  Adding a green lamp gave them Medium Clear, Approach Medium and Approach Limited.  Limited Clear was given the coveted *G* dwarf slot so that doesn't really count as a gain, but the C&O was forced to use *G* for Medium Clear on their non-virtual US&S N-3 signals so the extra flexibility is still there.  The only two dwarf indications not covered were Y/Y Approach Slow and G/G Clear, with both requiring a 4th lamp (Clear AND Approach Slow would require 5 lamps).  Again, while one might assume the signal engineers would want to put a gap between the greens such as G-Y-G-R that would be an incorrect assumption, especially where a 3-lamp is getting an upgrade to 4-lamp, such as a Rule 251 route going 261.

For comparison New Jersey Transit, which prefers to use non-virtual head dwarfs, must use 6-lamp dwarfs to get the same aspects that Conrail could squeeze from 4.  Here is a 6-lamp dwarf stack at the new DIVIDE interlocking displaying Medium Clear.



On the NJT RiverLINE NJT was responsible for the initial signaling design which resulted things like this 7-lamp monster at the Trenton Station.

But from the new signaling designs it appears that Conrail SAA has had a hand in subsequent modifications like the conversion of a mast signal to a dwarf south of Burlington which uses 4-lamp virtual headed dwarf.



Which even maintains a virtual R/R as seen below.

There are other instances on the RiverLINE of huge 5 and 6 lamp signals being converted into more compact varieties such as a Y-R-Y-R unit designed to give Approach Slow.

Let's take a quick look at some other popular speed signaled railroad.  In this rather unique Canadian example we see a US&S N-2 dwarf attached to an H-2 searchlight to create a 3-lamp dwarf signal capable of displaying Restricting and all the other slow speed indications.

 Because of its Lunar White fetish, the use of 4-lamp dwarves on CSX is common, but unfortunately its use of R/Y and R/G for the "Medium" indications means it is harder to employ virtual heads.   Of course it does make it easier to tell if turnouts are signaled for slow or medium speed such as this example on the re-signaled former Conrail Selkirk branch at CP-SK.  Had CSX stuck with NORAC an upgrade would have not needed any hardware changes.

Typical slow speed CSX 4-banger dwarf. 

 Even thought CSX could get away with using single light indications for it's slow speed signals, they also have a preference for virtual heads.  Using L/R for Restricting would have the benefit of a limited cost free bulb out protection

Slow Approach without all the flashing.

 More often than not CSX is going to spend the money on a twin stack of Unilens searchlight signals like these displaying Clear the old fashioned way at Huntington Ave in Baltimore.

As for the former Conrail parts of NS, I am sure that the virtual head system is still in use, but I also know that NS seems to be much more committed to using signal masts, even in instances where a simple 3 indication dwarf would do such as here at CP-WORKS.

What's the takeaway?  What is implied by a signal aspect chart can always be ignored or tweaked by a clever railroad just like a clever railroad can play fast and lose with signal progression or play cab signal tricks...but more on those later.