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Sunday, July 8, 2018

2018 PRR Main Line Trip Report

So it's been a year since my last comprehensive PRR Main Line trip report and a lot has changed in that time. First and foremost, NS's slow and steady re-signaling campaign has made a massive jump westward with new signals now going up along the entire western slope all the way to Pittsburgh on the Pittsburgh Line and Rochester on the Fort Wayne Line. This is a recent development and some of the masts in the Pittsburgh area are still sitting on the ground, however this marks the beginning of the end of the last great position lit terminal on a Class 1 railroad.

Twilight of the PLs at CP-PITT
In a small silver lining it appears that NS is expanding it's cab signaling to cover the Pittsburgh Gap between CP-EAST PITT and CP-KISKI on the Pittsburgh and Conemaugh Lines and CP-ROCHESTER on the Fort Wayne Line. All the new signals are going up with Rule 280a 'C' boards. This would mark a rare modern occurrence of a freight railroad installing a new safety system on it's own accord as the PTC mandate did quite a bit to forestall additional cab signal. Of course this will definitely ruin some of the aesthetics of the 3-4 track freight raceway between Pittsburgh and Rochester, however only about 3-4 automatic signal locations will be impacted.


It also appears that the former ALTO tower territory, resignaled in 2012, will not be getting Rule 280a 'C' boards, continuing to operate under Rule 261 with a single automatic on #2 track adjacent CP-HOMER. Other areas with back-to-back interlockings, like the Pittsburgh terminal, go not appear to be getting the same treatment despite the presence of some shortline operators that would need to get their engines cab signal equipped. NS is potentially increasing the number of signal blocks as the RoW has sprouted numerous new relay huts in odd locations, but these could just be for grade crossings or other secondary functions.

This new signal bridge is here to stay.  The westbound one will be replaced.

On the pneumatic front the entire Middle Division has been changed to electric M23 point machines. Over the hill CP-MG and CP-SO have both lost their pneumatic plants while CP-AR, CP-UN and CP-MO still retain them. West of Johnstown CP-CONPIT, CP-RAGE, CP-TRAFF, CP-WING and CP-HOME are still pneumatic, but will likely be converted soon. Interestingly, CP-C shows no work whatsoever in either the point machines or signals.

Missed my chance to take photos of the pneumatics at CP-SO and CP-MG :-(

In Pittsburgh specifically, signals will no longer play a role in protecting trains approaching the 20mph curve west of the downtown station. Instead of an Approach Medium -> Approach Slow -> Slow Clear (removed) progression, non-diveging trains will get Clear straight through. However the closely spaced interlockings will result in the use of R/R/*Y* Slow Approach signals. Also because the old Pitt signaled siding was removed, the new westbound signal at CP-PITT will only slow straight route signals and Restricting.

In the future trains through Pittsburgh will proceed on straight Clear signals.
While I have been able to document a lot of the infrastructure on this line before the charges started, I can't get to it all, so once again I am urging anyone nearby to get as many photos as you can before the past is gone for good :-(

Saturday, June 30, 2018

UPDATE: ALTO Tower Page Hi-Res Photos

So I took the time to re-process the photos from my 2004 trip to ALTO tower that formed the core of my 2011 blog post about the tower and its interior. The old photos had been edited for a 2004 web standard of 100-200k file sizes.  Although only taken on a 3MP camera, that still meant I could use the full resolution available without blowing up the page load time.


In addition, I streamed two photo processing sessions where I talked about the history of ALTO and the story of my visit to the tower along with all sorts of interesting factoids and hijinks.





Yeah that's right, I've getting into live streaming! Who says one can't squeeze content from a stone 😏


Sunday, June 24, 2018

Atlanta Terminal South Tower Demolished

One of the few bits of railroad history left in downtown Atlanta was torn down last week when wrecking crews came for the former Southern Railway Terminal South tower, one of the last surviving parts of the great Terminal Station that closed in 1972, itself razed for a Federal Building in 1979.  


While the brick structure was not in danger of fire, a number of large cracks had opened up on the walls and it could be assumed that the tower was less than structurally sound.


Unlike the Northeast and industrial Midwest, the South and West never featured large numbers of tower, especially high quality non-combustable ones with power interlocking machines.  A Georgia Rail history website could only list three surviving towers in the state, a number now reduced to two.  The Terminal South tower had also anchored the railfanning scene in the city and it is unknown at this time what might be able to replace it what with the unrelated re-signaling efforts that have been going on.

Saturday, June 16, 2018

Railroad Signals and the Materials of Yesteryear

NOTE:  This article first appeared in the Summer 2017 issue of The Trackside Photographer.

In 1967 young people were told that plastics were the future and the future did not disappoint.  Today the world is made out of plastic, carbon fibre, corrosion resistant lightweight alloys, high strength concrete and LEDs.  This technology has generally converted our world from one where stuff is expensive and people are cheap, to exactly the opposite.  I could go on and on about the many economic ramifications of this, but in essence "things" went from being crafted and artisan, to being so invisible that they might as well not matter.  Back in the day the Pennsylvania Railroad was the largest private employer in North America with over 300,000 employees, roughly the same as WalMart.  This vast army of workers was needed to polish, paint, lubricate and generally maintain all of the expensive, labor intensive technology that allowed humans to move at speeds faster than brisk walk.  Replacing the materials of old was part and parcel to being able to replace the workers that cared for them, however as we charge into the middle of the 21st century some of these materials have soldiered on in the service of railroad signaling and, until their inevitable replacement, they provide a window into the pre-digital industrial age.

CSX Washington Sub - South Orange Interlocking
Steel and iron are the stereotypical railroad materials as demand for bridges, rails and locomotives practically created the modern steel industry.  Of course steel wasn't just used for girders and boilers. Back in the day this was the only metal one had available for structural components of any size and before the advent of plastic or other composites, metal was one of the only materials available with an adequate strength to weight ratio.  Stronger, weather proof and more durable than wood, iron and steel became the materials of choice ofr railroad signals and signal structures.  This US&S style N color light signal mast shown above is almost completely made of iron and steel, right down to the base.  Cast iron housing and brackets, sheet steel backing, steel pipe mast, strap iron ladder work, heck, even the signal wires are sheathed in iron.

CSX Philly Sub - MP 80 Auto Signal "Whitemarsh"
Cheap and easy to stamp, cut, forge or cast, steel was everywhere, but it's suffers from a major weakness against air and water.  The scourge of rust requires care and paint, and paint requires workers to apply and remove.  In the 21st century aluminum is cheap and plentiful.  Lightweight and rust free, any signal made of aluminum will look as good on the day it is installed as the day it is removed perhaps decades in the future without needing so much as a man hour of skilled labour.

CSX Cumberland Sub - Paterson Creek interlocking

Also used for bridges and track structure, wood was the plastic of its day.  Light and easy to shape, it also has tensile strength allowing it to span distances in a way that stone or concrete cannot.  Although it was excluded from most signal structures, wood was employed in pole lines to support the signaling and telegraph wires that carried little bits of voltage from one signal location to the next.  Unlike steel, stuff can be easily attached to wood with nails or screws and, somewhat surprisingly, wooden poles can also last decades after being impregnated with petrochemical tars.  However modern technology found other ways to eliminate the wooden pole lines by replacing the wires they carried with fiber optics or wireless signals.

D&H 'QS" Interlocking, Mechanicville, NY
Surprisingly, cotton was an important material in railroad signaling.  Before the advent of PVC sheath insulation, large signal cables were wrapped in cotton impregnated with tar to keep out the elements.  Cotton insulated cables went hand in hand with the pole line concept as attempting to bury such a cable would quickly lead to its failure.  Damage vulnerable to wind, snow, rain and trees, this was accepted a cost of doing business.

PRR 138kv Transmission Line near Martic Forge, PA
From the smallest telegraph wire to the thickest high voltage transmission cable, copper carried the electrons that powered the signals and sent the data.  Synonymous with the term "electrical conductor" to this day, copper was generally replaced by aluminum braids in power applications and of course its role in data transmission was tied to the pole line . Ultimately railroads did all they could to get out of the power transmission business, in some cases going as far to replace copper cable with solid state solar panels.

CP-MIDWAY - Port Road Branch
Large ceramic insulators met the same fate as the copper wire when the business of providing signal power was turned over to the local utilities.  Outsourcing is the name of the game in the 21st century.  It made no sense for railroads to act as power companies, employing linemen and stocking electrical hardware such as this.

CP-SLOPE, Altoona, PA.
PCB's are probably the best class of material for insulating transformers being non-flammable and possessing a high dielectric coefficient.  Unfortunately they also cause cancer and persist in the environment almost indefinitely.  All the more motivation for railroads to stop running their own power grids.

CSX Cumberland Sub - Magnolia, WV
 Glass was the insulator of choice for low voltage signal and telegraph wires running along side the power supply lines on the poles.  Edging out ceramic in the same use case, the sparking glass insulators made railroad poles a look a bit like Christmas trees.  Replaced at first by cheap rubber and plastic models and ultimately by wireless, glass insulators became a staple of country antique shoppes and the preferred target of rural target shooters.


More expensive than its pole line cousin, optical glass collected the light from the low wattage signal bulbs and and protected it 1-2 miles down the track for approaching trains to see.  Most color light signal lenses consisted of an inner colored glass filter assembly with an outer Fresnel lens that focused the beam.  Today these have been replaced by high intensity LED's that often do not need a focusing lens, making do with a cheap clear plastic cover.

CP-RADE, Radebaugh, PA
Compressed air was the power source of choice for many early power interlocking installations.  Not only were air operated switch machines simple and cheap, it was also easy to safety control the flow of air using low voltage electrical circuits passing through an electro-machanical interlocking machine.  Of course air was only cheap as long as the workers needed to keep the lines dry and leak free were also cheap.  Today pneumatic switch machines are fading fast in the presence of bullet proof, high voltage electric machines.

CP-TRAFF, Trafford, PA
Silver paint is typically applied to relay huts and cabinets to reflect the sun and keep internal temperatures low.  In this case the need for painting has been replaced by corrosion free shiny materials and compact air conditioners.

CP-HAWSTONE, Lewistown, PA
Lead acid batteries were once provided in large quantities for when the railroad supplied power suffered some sort of outage, as was frequently the case in the pole line era.  Because the batteries would vent hydrogen gas as they charged and discharged, they were stored in concrete "wells", outside the relay huts where there was no risk of explosion.  Today improvements in battery technology and power reliability have made such large bulky backup power arrangements unnecessary.

PRR OVERBROOK tower.
Relays are constructs of copper coils moving silver plated electrical contacts to make and break electrical circuits, all sealed up in a glass envelope.  Once the standard unit of electronic logic until the advent of the transistor, the function of relays was duplicated by solid state gizmos such as transistors.  Relay logic was standardized across vendors and can't be hacked, but changes are costly and time consuming to implement, making software based alternatives far more attractive.

CSX Cumberland Sub MP 130 Auto Signal "Drywall"
Up through the middle of the 20th century railroads were once at the vanguard of technical innovation, leading the way in telecommunications, computing and material science.  While today these technologies and materials of yesteryear can make railroads seem like an under-funded anachronism, a different view shows how well the engineering of the past has stood the test of time.  While the materials of today are in many ways superior, they lack much of the spirit of what came before.  A spirit created by human hands crafting, fitting and maintaining the materials of yesteryear from one century to the next.

Sunday, June 3, 2018

Caught on Camera: Bobbing SEPTA Main Line Signals

Several years ago I discussed the topic of relay logic and how it can create interesting signal displays as they change from one aspect to the next.  (Usually this involves a change from some form of Clear to some form of Restricted Proceed as that involves two or more discrete relay flips.)  Well last week I had taken a trip to the SEPTA North Broad station, just south of the busy 16TH ST JCT, to photograph the last remaining AEM-7 locomotives in operation.  At one point, towards the tail end of the peak period, the track 1 signal on the Milepost 2.9 automatic signal bridge began to cycle between Approach Medium, Approach and Stop and Proceed.  The northbound home signal at 16TH ST was displaying Medium Clear, so Approach Medium was indeed the correct indication, however the signal continued to move between the three at a fairly brisk clip indicating that the track circuit between there and the interlocking was moving between an occupied and an unoccupied state, a phenomena known as "bobbing".



As time went on the rate of the cycling increased and as soon as the AEM-7 led push-pull on the adjacent track 2 cleared tthe approach block to 16TH ST, that signal began to bob as well, although only between Approach and Stop and Proceed. In due time a northbound train approached the 29-1 signal and I can only imagine what the crew was thinking as they not only watched the wayside signal change ahead of them, but also endured a constant stream of cab signal flips. As one might have expected, the train passed the malfunctioning signal at Restricted speed and shortly thereafter the track 2 signal was also brought down to the Stop and Proceed position full time by an adjacent northbound train.



After the two trains passed whatever temporary fault condition that existed was resolved and the MP 2.9 automatic signals went back to normal operation.  There was a later service disruption at the junction, but it appeared to be related to some sort of stuck switch or disabled train. The funny thing was that this wasn't even my only recent encounter with bobbing signals as I also caught two northbound signals at Milepost 69.6 on the Amtrak's Southern NEC also bobbing.



Some bobbing track circuits can be fixed with a few simple adjustments.  Others can be quite stubborn and can linger for weeks.  Some parts of the southern NEC had bobbing circuit conditions that had been around for years, often where electric movements on one trackcould cause an adjacent track to temporarily show occupied.




Sunday, May 27, 2018

A Few Bits of News

I haven't had much to report on lately, but I did save up a few random news items, some good, some bad.  On the good side of things I finally discovered why the former DRG&W route has not seen its new signaling cut over between Helper, UT and Grand Junction, CO since it I first spotted it in 2012.  Well, Union Pacific has decided not to PTC equip the line due to low traffic volumes, so that's cool.


The former ATSF transcon in Illinois is seeing increasing amounts of re-signaling so if you live in the area get out soon to document the searchlights and signal bridges.

Edelstein, IL
While no stranger to re-signaling efforts, the last searchlight signals on the freight level of Blue Island Jct are now on tap for replacement.


I had also reported on the NS Harrisburg Line re-signaling between Philadelphia and Reading.  At first glance it appears that CP-TITUS, at the junction of the old southern Belt Line and the Main Line into downtown, was going to be spared, but as I have learned many times before, looks can be deceiving and the new double crossover between here and CP-BIRD will replace CP-TITUS in its function as a junction.  Ultimately that is all CP-TITUS is, a double crossover, just with a lot more complexity and it's otherwise isolated location, accessible only through the locked gate of a private power facility, made NS relocate the track split a mile to the east.



Sunday, May 20, 2018

LIRR Reduced Aspect Signals

Well it looks like the LIRR has decided to jump into the same pool as Metro-North and SEPTA by adopting a Go, No-Go signal system in conjunction with cab signals.  However, instead of following the practice of either MNRR or SEPTA, the LIRR has decided to do things their own way.

No Restricting
For a bit of context, the LIRR adopted a Rule 562 (no waysides except at interlockings) type system way back in the 1970's, a decade or more before MNRR went with it's no famous Go, No-Go signals.  The LIRR simply used full signals at interlockings, seeing no need to differentiate wayside ABS territory from non-wayside ABS territory. 

No Cab Speed
 In designing a reduced aspect system, the LIRR faces a few challenges that do not apply to either SEPTA or Metro North.  First, the LIRR is not a NORAC member, but runs on NORAC territory between HAROLD and Penn Station, so new signals should try to avoid confusion with NORAC.  Metro North does not run on foreign territory so it had more freedom in it's design.  Second, the LIRR already deployed a new color light system so a new, new system should also not conflict with that.  Thirdly, the LIRR employs a Manual Block system that must have some compatibility with the new indications.

No Absolute Block


The result is a series of 6 signal indications, instead of the more typical 3 (Stop, Cab Speed, Absolute Block or Restricting).  The LIRR not only uses both Restricting and Absolute Block, but also two additional ones Exclusive to the LIRR.  These are Slow Cab Speed and Restricting Cab Speed.  The difference is that the first relieves the engineer from having to stop within one half the range of vision etc.  "Restricted Proceed" even explicitly handles the not uncommon situation where something in the interlocking creates the need for a call on, but beyond that everything is ok.


LIRR is also leaning heavily on the lunar white lams in order to differentiate all of the new signals from their current crop of color light signals.  The only aspects not using lunar are Stop and Restricting, both of which already exist in classrooms. 

Something for everyone
The expectation is that these will be used on dwarf signals placed at rebuilt interlockings away from major terminals and other congestion zones.  If these can spreads to the entire system remains to be seen, but both the HAROLD and JAMAICA terminal interlockings are getting new standard color lights. The first interlockings to get the new signals will be those on the outer Ronkonkoma Branch where a double track project is under way.

Sunday, May 13, 2018

All Askew - Remaining Users of Offset Auto Signals

Back in the day, setting the heads of a multi-headed signal on opposite sides of the mast was an effective way as marking a signal as an automatic.  Although the presence of a number plate was an accepted and inexpensive way of doing the same thing, reflector technology wasn't as advanced as it is today.  Some railroads even went as far as placing markers on single headed automatics simply to make them more visually distinctive.


However as time went on this practice, like many, was seen as a luxury that did little for safety.  Since the 1980's most railroads have placed their signal head in line, regardless of automatic status.  However there are still a few that have stuck with the old ways.

Canadian National / Canadian Pacific

The CROR signal ruleset is perhaps the more strict when it comes to offset head placement as it is the only option to designate a signal as automatic as number plates can also appear on absolute signals (on absolute signals plates are used to denote the lever number).  On single head signals left hand placement is used to provide the distinction in addition to absolute signals always having two or more heads.


Unfortunately, as far as I can tell this policy does not apply to CN and CP's United States operations, although some vestiges exist like these somewhat modern unilens signals on the former D&H.


Flordia East Coast

Regional operators often become museums of signaling practice and in this regard the FEC has preserved the practice of offset head placement.  The FEC also uses a robust cab signaling system so this is even more interesting single they could probably eliminate waysides entirely if they wanted to.


Former Boston and Maine (Guilford Rail System / MBTA)

Public transport agencies are another place where traditional signaling practices can live on and combined with a regional freight operator we have the former Boston and Main system as our final holdout on the use of offset signal heads. Some of the newer heads are a bit less offset than others, but it's clearly still a thing.



Well that's all the ones I am aware of at this point.  There are probably others (I'm omitting the Reading and Northern cause that's somewhat of a special case). Please let me know if you know of any that I have missed.

Saturday, May 5, 2018

New York Media Picks Up On True Cause of Subway Meltdown

I wanted to give a shout out to someone at the New York Times for reporting on the real cost of "safety" improvements.  For those of you who aren't aware, the NYC Subway is currently experiencing a meltdown due to high ridership and delays that quickly propagate through an at-capacity system.  The NYCTA/MTA are quick to blame the high ridershi or generic "aging infrastructure", however a Times reporter correctly put the blame squarely on two decisions the MTA made under the guise of improving safety.
One of these was a decision to drastically expand the number of speed control signals throughout the system.  Once only used in the locations most at risk of a speed related derailment, they have been placed all over the system in an effort to remove operator skill from the equation of train operation.  What the MTA didn't forsee (and what anyone familiar with this topic easily could) was that the speed control signals induced operators to reducing speed far below what should have been allowed.  This is because operators are not only punished for getting tripped by the Automatic Train Stop, but also because the speed control signals are not well maintained or calibrated and will often release 5-10 mph below the speeds they should.  This results in highly conservative train operation.  The net result was that all of the slack time in the system was used up dealing with speed control signals so now even the smallest delay will persist for hours, affecting both the initially delayed train and every train behind it.

4 one shot timer signals at Canal St replacing what had once been left to the operator's skill.

We can see PTC having the same effect with SEPTA, Amtrak and Metro North all having to increase their running times to account for the slower speeds.  Speed control thresholds don't take existing safety margins into account and calculated braking curves are also highly conservative making all trains run like they have a grandmother at the controls. All of this will reduce capacity and make making up time a concept of the past.

Some insiders have stated that the true reason behind the slow down of trains using speed control signals is to gain leverage over the unionized workforce in contract negotiations.  Not only does removing skill from the position allow for the recruitment of younger or less skilled workers, it also prevents rulebook slowdowns, the Transit Worker's union only weapon since strikes are banned by state law.  The idea was to slow the system down proactively so that work actions would lose their power (think of the frog in the boiling pot of water). However now the scuttlebutt is that management simply doesn't know what it's doing and there is no real strategy behind the slowdowns aside from doing what the safety consultants recommend. 

An interesting point of comparison is The PATH railroad that runs between New York and Newark.  It uses pretty much the same equipment and signaling system, but the timers are timed properly so that the operators can run right at them at the prescribed speed and not get tripped. In fact, before 2010 the PATH equipment didn't even come with speedometers, requiring the engineers to know how fast they were going on instinct.



Anyway it will be interesting to see if the MTA is forced to back down from its position of slowing down the system in the name of "safety" or if they will stay the course and try to extract billions from the government for such Wunderwaffen as CBTC. Which, I should mention, is only expected to deliver an additional 2 tph on the 7 line, resulting in a frequency that is still below historic levels when operators were given the freedom to use their skills to maintain the schedule.. 

https://www.nytimes.com/interactive/2018/05/09/nyregion/subway-crisis-mta-decisions-signals-rules.html

Monday, April 30, 2018

Racine PLs Removed! A Chicago Icon is No More

Well the famous "Racine" position light signals inbound towards the north end of Chicago Union Station were suddenly replaced last week.  If anyone was ever wondering why there were PRR position lights in Milwaukee Road territory, since taken over by METRA, it is because the former PRR Panhandle Route to Chicago came up the west side of the city, took a right turn and entered Union Station from the north. (This was discussed in my article on Tower A-2).


This was not part of a re-signaling effort, the signals were cut into the existing interlocking logic one by one over the course of  several nights.  The replacements were METRA standard non-Darth LED traffic lights.  Fortunately the bomb-proof PRR signal gantry was re-used and will probably live on until the end of time.

Photo courtesy Robert Jordan
While located at the Racine St grade crossing, the signals are officially part of CP-MORGAN, a remote interlocking controlled from TOWER A-2. There are two facing point crossovers with movements made at Restricting speed.  Under Metra signal rules the lower LED heads will display R and L.

Photo courtesy Robert Jordan
The signals at the other end of CP-MORGAN were converted to searchlights sometime in the 1980's.  Word is that this will be replaced in the near future.


Saturday, April 28, 2018

Last C&O Main Line Signal Bridge and Covington CPLs Fall

Well a major holdout of classic signals is now gone.  Just south of the Ohio River on the route of Amtrak's Cardinal, the juncton of the former C&O and L&N main lines had featured both B&O and C&O signals until just a few weeks ago.  One of these, at NX Cabin, was the last C&O signal bridge left on the old C&O Main Line between Newport News and Cincinatti.



This island of signaling had survived because it was involved in a re-signaling programme in the 80's or early 90's and was lower down on the priority list.  The main attraction was KC junction, which feature a number of 5 orbital CPL's and some strange hybrid C&O signal bridges that were refitted with B&O CPLs during the re-signaling process.  The ones coming off the former C&O main line were notable for their comically large sun shade.
 

KC junction also featured a massive 3 story L&N interlocking tower, but it was demolished sometime within the last 10 years.  I do not know the state of the CPLs at the adjacent OB Cabin (Ohio Bridge) or A interlocking in Cincinatti, but the smart money is that they have also been removed.




Saturday, April 14, 2018

Denver Light Rail Signaling - Checking All the Boxes

From time to time I have brought up some of the quirks inherent to North American light rail signaling systems.  Because they exist in a regulatory and cost grey area (not really railroads, not really subways, able to stop on sight in traffic, etc) the signaling systems they employ tend to be very economical.  Well this past summer I traveled to Denver and rode around on its extensive light rail network.  There I noticed that the RTD light rail had methodically checked off every box on the light rail signaling checklist and I figured I should share it here.

1.) Missing Wrong Direction Signals 


See that little red circle?  Yeah, that's plated as a signal because the RTD's commitment to single direction ABS is so complete that all wrong direction movements need to get talked past the stop disc at the next interlocking.

2.) No Distinction Between Auto and Interlocking Signals.


See any difference between the ID plate on the interlocking signals in the first picture and the ABS signal in the second?  No?  Well that's par for the course on a light rail system.

3.) ATS


Light rail systems don't uniformly lack speed and signal enforcement.  They just opt for the budget versions.  RTD Light Rail has some sort of loop based ATS on its main line sections, but the operators weren't too helpful in providing the details on how it worked.  Of course where ATS proves impractical one gets a nice little sign.

4.)  Single Headed Signals.



Light rail systems hate confusing drivers with multiple signal heads, so flashing aspects warn of diverging movements.

5.) Vehicle, Signal Thyself


Dispatchers cost money, so LRVs simply set their destination and let track mounted sensors do the rest.

6.) New Lines, New Rules


How can consultants bill those hours if they just say to stick with the same old thing?  Of course the line that just opened in 2017 would have some new signal rules requiring a second head!

7.) US&S N-3's



You look hard enough around a large light rail system and you'll find a US&S style N-3 signal head 😏

Did I miss any?  Throw something in the comments and I'll see if I can find an RTD example ;-)