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Wednesday, December 28, 2011

PRR Main Line Survey 2009 Part 10 (CP-RADE to CP-WEST PITT)

Well for those of you who have stayed with me on this odyssey of signaling across Pennsylvania we have reached the final leg of our Journey between Greensburg, PA and Pittsburgh itself. The daylight was beginning to fail at this point so I apologize for the decreased photographic quality.

The relevant track charts for this segment can be found here.

Beginning at Greensburg it is worthwhile mentioning an interesting feature of the right of way that important to the signaling in the area. You may have noticed in part 3.2 that SW tower at Southwest Junction had a western section where the 4-track right of way shrank to three tracks for a pair of tunnels. I mentioned that past CP-CONPIT the main line took off overland across a plateau to reach Pittsburgh directly instead of following the Conemaugh River. This resulted in a steeper grade profile as well as a number of bottlenecks in the Greensburg area in the form of tunnels. The first was located directly east of the station and was eliminated in the 1890's, the second set of tunnels hung around a lot longer and remained an operational headache.

Known as the Radebaugh tunnels after the community west of Greensburgh (which had its own tunnel) the first was built in 1852 as part of the original Main Line project and nearly derailed the entire enterprise as the cost and delays of tunneling began to give the Philadelphia area investors cold feet. The original tunnel was very tight and built on a curvy alignment through the local drainage divide between the Conemaugh and Monongahela rivers. In the 1890's a new, larger tunnel was built on a more direct alignment, at first replacing the original tunnel until traffic levels pressed the 1850's bore back into service to carry a third main track. You can see the two tunnel alignments on this Wiki Map. ... =Radebaugh

Still, three tunnel tracks on a four track line a bottleneck makes, but adding a 4th track or simply removing the tunnel never became a priority for the PRR so they did the best they could with interlocking design. Directly on each side of the new 1890's tunnel the 3 tracks shrank to 2 via a parallel shift layout with freight track 1 having the forced diverge at each. Track #4, also designated for freight, used the pimple alignment of the 1850's tunnel allowing the designated passenger tracks 2 and 3 the straight shot through.

In 1965 the waning PRR showed some of its old magic when new tunnel was daylighted in a project where the overburden was first removed and then in the space of 11 hours the tunnel roof was blasted and track re-laid with the RoW being widened over time. Track #4 remained in use through the old tunnel on the alternate alignment until the deluge from Hurricane Agnes collapsed it in 1972. The 1980 CTC project under Conrail did the rest permanently making the line two-tracks.

Anyway as I said all this was relevant to signaling as both SW tower east of the tunnels and RG tower, west of the tunnels, were built to deal with the bottleneck. Here we see the location of the new tunnel now just an open cut. In the right of the picture there is an interesting signal facing away from us for traffic on the branch line which is labeled R08. This is a distant signal to the upcoming interlocking and a vestage of the old PRR Manual Block system.

In this view taken in 2004 we see R08 in its original configuration as a PRR Position Light. This signal could display, Approach Medium, Approach and Caution. Approach Medium would display when a train coming off the branch line was had a proceed indication like Medium Clear and Approach would display if the interlocking was showing a Stop indication. Both would show that the track circuited approach block was clear, however if it was not the signal would display a Caution signal which on a PRR PL is \ over a marker light as shown in this photo.

Saturday, December 24, 2011

PHOTOS: Amtrak THORN Tower

Those of you who read my earlier essays on the signaling of the PRR Main Line might remember a bit about THORN tower in Thorndale, PA (where else!). Situated at the junction of the original PRR Main Line and the Low Grade Extension of the Trenton Cutoff, THORN interlocking proper consisted of a 6-track full crossover with the two track Low Grade Extension to the east and a small yard and helper base to the west, both sandwiched in between the two main tracks of the Main Line. Today THORN tower remains active as part of Amtrak's Harrisburg Line having seen many changes over its 70 years in operation.

THORN tower was built in 1938 and at the time it represented a bold form if new technology on the traditionalist Pennsylvania Railroad. The PRR had been a strong proponent of the traditional block system with Block and Interlocking Stations spaced even intervals along the line with Block Operators passing trains from one to another. As the PRR was a wealthy railroad and could afford the expense of building interlocking plants where many other railroads would make do with hand throw switches and the Automatic Block System. As the cost of technology began to drop in relation to labor Centralized Traffic Control began to be embraced by PRR rivals such as New York Central. Intended to replace train orders on long single-track lines, CTC pulse-code technology could nevertheless allow multiple interlockings of any configuration to be worked from a single location. While the PRR would continue to rely on the individual Block Station until the end, it did install several significant CTC projects with THORN being one of them.

THORN's territory stretched from MP 25.3 to MP 36.6 on the Main Line and also included the Philadelphia and Trenton Low Grade Extension between those two points as well. In addition to its own namesake interlocking, THORN had CTC control over DOWNS, GLEN and DALE interlockings to the east and CALN interlocking to the west. While today CTC implies bi-directional operation, the PRR was content to use the technology for simple remote control and most of the routes were left operating under single direction ABS.

The Penn Central era brought some minor reductions to THORN's plant with the Low Grade extension being reduced to a single bi-directional track and the line between GLEN and PAOLI being reduced from 4 tracks to 3, with the center track being bi-directional.

Under Amtrak the plant shrank further with the Low Grade Extension being completely abandoned, the Thorndale yard being almost completely removed and the 3rd track between GLEN and PAOLI being ripped out due to the loss of through freight service on the Main Line in the early 1980's. However most of the interlocking layouts were kept the same due to the costs involved with modifying the logic. Here is how the territory looked in 1992.

In 1994 the closure of Paoli Shoppes due to massive PCB comtamination forced SEPTA to build a new terminal Yard in Frazer, PA for its popular R5 commuter service. This added a simple interlocking for trains to enter/exit the yard and to turn back just east of GLEN intelrocking. The old DALE interlocking, now little more than a Control Point was eliminated and the few local freight accessing the Main Line would queue up at the home signal at GLEN.

While even more changes are planned for the Harrisburg Line, in 2010 THORN and its territory are much the same as they were in 2005 when I was able to commission a survey of the tower and its interlocking plant. Some of the photos had to sit on ice for a few years, but they have been recently processed and posted for you all to enjoy. Photos that were releasable at the time were processed at a lower resolution due to the conventions of screen sizes and internet connectivity at the time.

THORN tower is an identical twin to the previously discussed COLA tower, which like THORN was a PRR CTC tower built in 1937. Both these towers were built in conjunction with the electrification of the PRR Main and Low Grade freight lines to Harrisburg. It is a two story brick building with no trademark bay window. It could be considered a forerunner of the 1940's towers built up and down the Northeast Corridor and discussed in the overseas section. The tower has a number of subtle art deco flourishes as well as a pair of interlocking illumination floodlights (one currently active). Also on the right side of the tower note the tower emergency horn which, in theory, can be used to stop trains moving through the plant.

Thursday, December 22, 2011

Good News From Down Under

Actually its not Australia I'm talking about today, but New Zealand.  Recently I had heard that a re-signaling scheme had been carried out on the Hutt Valley Line, the old signals of which actually had their own website.  Well today I learned that the project only re-directed CTC control from a local US&S panel to a dispatch office in Wellington.  Even better all the original relay based CTC interlockings were left untouched.

Ok, that's pretty minor, but the news gets better.  While the US&S Model 14 interlocking machines in the US are marching towards extinction with the recent re-signaling projects at ALTO, UNION and WB, US&S parent company Westinghouse did sell power frames based on that same technology overseas to mostly British commonwealth countries as the style L, K, N and B miniature lever frames. They are basically US&S frames just with the levers working back and forth instead of side to side (so the poor signalmen wouldn't get confused ;-) )  Anyway these are about as rare as their breathern here in the United States with only a handful of examples still in main line operation in the UK and South Africa.  Well today I learned that again, despite some minor re-signaling, not only is the large Style L frame controlling the Wellington, NZ terminal still in service, but it was actually upgraded with three flat panel displays replacing its old bulb lit model board.  Talk about a clash of technologies!!

Not only does that frame survive, but so do three others on the North Island Main Trunk at Tawa, Porirua and Plimmerton with Porirua being in use daily and only Tawa being "generally known" about.  Here is a page that has some more up to date information on the Style L machines in New Zealand.

Anyway its nice to know that even if power frames vanish from the United States they can still be found in some nice vacation destinations overseas.  And then if those go you can always check out the pneumatically actuated Style V machines installed on London Transport up through 1999!!  

Monday, December 12, 2011

Wee Bit of Good Searchlight News

Just saw that out on the former Southern Pacific line in Mojave, CA the MP 377 signal bridge is being taken down for what are probably justified structural issues.  However the two track gantry with its 4 searchlight signals is being replaced with a pair of searchlight masts.  Huzzah!!  Finally, a Class 1 railroad that isn't afraid to Reduce, Reuse and/or Recycle.



The searchlight masts definitely appear to be used, but hey, I'll take it.

Sunday, December 11, 2011

C&O Main Line Re-Signaling Plan

Well the bad news is in and if you have plans to ride the Cardinal do it now because most of the remaining C&O signaling on the main line will be gone by the end of next year.  Already the signaling has been moving east from Montgomery, but I just learned that already the old signals have been removed between OX Cabin and Clifton Forge on the east slope of the Allegheny slope.  Next year the plan is to fully denude everything between there and Hinton including White Sulfur Springs and the summit at Tuckahoe.  Hopefully there will be something left when I ride the dome car on the Cardinal next season .  I'm feeling really bad that I didn't seize the opportunity this year, although I do have two surveys of the signaling on the line of marginal quality.

Saturday, December 10, 2011

PRR Main Line Survey 2009 Part 9 (CP-JW to SW)

As we enter the final zone of signaling on the PRR Main Line I thought it might be worthwhile to summarize things a little in relation to where the signaling in each section dates from and who installed it as we travel from Philadelphia to Pittsburgh to provide a bit of perspective.

  • MP 000 -> MP 067 - Pennsylvania Railroad - Relay + Electromechanical - 1940s
  • MP 067 -> MP 104 - Amtrak - Solid State - 2008
  • MP 105 -> MP 231 - Conrail - Solid State (GE Series 6) + Relay - 1990
  • MP 231 -> MP 237 - Pennsylvania Railroad - Relay (US&S 504 CTC) + Electromechanical - 1950s
  • MP 237 -> MP 265 - Conrail - Solid State (GE Series 6) + Relay - 1994
  • MP 265 -> MP 274 - Norfolk Southern - Solid State - 2000
  • MP 274 -> MP 290 - Conrail - Relay (no interlockings) - 1990
  • MP 290 -> MP 353 - Conrail - Relay(? Listed as D601 system) - 1980

Not sure what conclusions can really be drawn here, but as we pass Johnstown we enter into the earliest of the re-signaling projects that was intended to replace the original PRR signaling. The Pittsburgh Division interlocking charts indexed at Multimodal Ways list the interlocking system used in this section as D601 (details of which I was unable to locate) and the interlocking sheets are the last series of which were hand drafted. I suspect this is a late model of all-relay based CTC technology that first became popular in the 1950's and was eventually supplanted by the new SSI systems in the 1980's.

One side effect of being an early adopter was that none of the PRR signal bridges were replaced with Position Light mast signals. In 1980 railroads still had many first generation road switchers in service and they were designed to run long-hood forward so signals still had to be mounted to the right of the track (Engineer's Side). This meant either gantries or tall bracket masts were needed on double track CTC lines. The downside of this is that between MP 290 and MP 353 there has been significant attrition of position lights because by the time the gantries finally became life expired Conrail has stopped installing position light mast signals to replace gantries like they had between MP 105 and MP 231.

We begin our journey at Johnstown on a new track diagram, but still in three track territory.

Past CP-C we come to CP-JW, which used to be remote C tower with direct wire control from C's Model 14 machine. CP-JW was re-signaled when C tower was closed and had all new signals installed. Like CP-AO, CP-JW is on track 1 only and provides access to the Johnstown yard and helper base from the west. As such there is a power split point derail on the yard track. The signal on the main track is an innovative model that allows the whole signal head unit to be cranked down to ground level for servicing. While this saves on maintainers having to climb the ladder, it requires that the signal be taken out of service, a complicated process that involves the dispatcher and transmitting paperwork to trains. Simply working on a traditional signal will simply result in a dark head, which is covered by standard rules. The yard track has a simple 3-stack Safetran modular dwarf signal that can display 1 or 2 lamp combinations.

I should mention here that when Conrail re-signaled the lines it was more likely to connect the existing interlocking appliances and signals to the new vital logic controllers. Today most railroads prefer to install brand new signals and get all the testing out of the way before taking the old signals out of service and placing the new ones in service in one go. In a literal cut-over the interlocking would have extended downtime to test all of the splices were done properly. CP-C and CP-JW were both re-signaled in this new fashion.

The new relay hut was placed directly adjacent to the old one. It looks like in 2003 someone was still producing new Conrail style ID boards.

A traditional mast signal was erected at the west end of the interlocking in the new NS "tombstone" variety. The switch at CP-JW leads to unsignaled territory, but CP-JW is also the track 1 distant to CP-C and grants a lower head green lamp for Approach Medium aspects.

Just past the Johnstown Amtrak station we pass the 2752E signal mounted on a late model PRR gantry. The position light signals on this bridge apply to track 2 only and it is the eastbound distant to CP-C on track 2. This section of the line had its block signals refreshed by Conrail in the 1990's so their style of re-numbering applies. I should also point out that while this looks like a normal three track line, track three on the left is not like the others. It will diverge from tracks 1 and 2 and cross the Conemaugh River to run down the other side to CP-CONPIT. Singles lines with tracks that take different paths from point A to point B is not a unique occurrence and such routes are often called Slow Routes or Turkey Paths. In this case the time penalty for a track 3 routing is 15 minutes and every so often this train suffers the hit then tracks 1 and 2 develop blockages.

Also note where the second island platform for the Johnstown station used to sit.

Tuesday, December 6, 2011

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.

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.

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.

Monday, December 5, 2011

Finding a Blue Lining

We all know the railroads have been in overdrive lately resignaling even perfectly functional interlockings on non-pole line CTC routes.  Well I have managed to find one small silver, or should I say blue lining to all of this.  Recently NS re-signaled three interlockings on the western end of the Conemaugh Line near Pittsburgh.  CP-HERR, CP-ENTA and CP-SHARP were all Penn Central era interlockings with mostly solid steel signal gantries and cantilevers, position lights and pneumatic point machines.  Well NS removed the whole lot as they reconfigured Enta Yard.  However at both rebuilt interlockings NS bothered to install brand new Conrail blue location signs on the relay huts.  I guess its a nice thought, but I would have preferred they leave the interlocking appliances alone to begin with.

Here we see the original relay hut with the new cantilever mast.

And the new relay hut with the new sign.

Wednesday, November 30, 2011

PRR Main Line Survey 2009 Part 8 (CP-UN to CP-C)

Well we have reached the summit of the PRR at Gallitzin and it is time to coast down the West Slope. While not as dramatic as the East Slope and its Horseshoe Curve the West Slope is still a helper district, is three tracks and has a good bit of cool signaling.

The following track diagram will apply to this part.

If you forgot all of the photos can be seen at: ... art-3.html

After leaving CP-UN we pass under the 2493 automatic, which is for westbound movements on tracks 3 and 4 only. Yes you heard me right, between CP-UN and CP-MO the tracks are renumbered 0 through 4 due to the presence of two siding tracks on the other alignment and thus track 3 becomes 4, 2 becomes 3 and we have a new tracks 2 and 0. This automatic is also distant to CP-MO, mounted on a two track late model gantry and if you look at the bottom | you can see the old mounting bracket for a Limited speed triangle.

Thursday, November 17, 2011


Last May Metra closed the last interlocking tower on its Electric Division running south out of Chicago. This was the former Illinois Central suburban routes electrified at 1500 vDC in the 1920's. Like many other high density suburban routes the Metra Electric continued to rely on on manned towers well into the CTC to deal with the traffic volume and complexity of operations. However over the last few years Metra has invested in closing the 3 towers on the line, Randolph Street (terminal office with some sort of relay machine), 67th St and Kensington.

Now I had always assumed that Kensington Tower would be the last to go because it was arguably more complex and also involved a crossing at grade of the CNIC freight main line by the South Shore Line, which diverged from the Metra Electric line there. Because of the three separate entities involved I figured a fight over funding and service quality would keep Kensington open. I was also under the impression that 67th St was some sort of more modern type relay based machine and Kensington was an ancient GRS pistol grip frame as that was how each was listed on the large Jon Roma list of towers. Turns out I had it completely backwards. Kensington had been converted to a relay plant controlled by a GRS TrafficMaster CTC console (and was originally a US&S plant), while 67th St had the GRS machine. Also I thought 67th St was some small office buried somewhere around the junction, while in reality it was a full on tower hiding in plain sight next to the tracks. I just never noticed it.

Anyway, I spotted this Blog piece on the closing of the last of the Metra Electric div towers and along with a good history of the tower (which you should read) there was a very tantalizing interior photo of the GRS Model 5 machine inside. I managed to track down the man who took the photos who was nice enough to send me his whole set on CD with permission to post them online and use them in my photo essays. The photos have been unmodified (apart from renaming) and left at their original resolutions to preserve the details inside the tower so you might want to click "View Image" to get the full amount of detail. The entire set may be viewed here.

Jumping right in, here is the best photo of 67th St that was provided showing a Metra Highliner EMU making a station stop in fairly typical Chicago weather. The tower is a large rectangular monolith with no typical "tower" accouterments, which is why I probably mistook it for a substation. What gives it away however is the massive arm bundles of signaling wires running out from the tower onto a local concrete pole line.  67th Street is located at the junction of the IC Main Line and the electrified South Chicago Branch which runs to a station only a short distance from the Quad Draws at CP-509.

 I should probably provide a little reference at this point. Here is a line guide to the Metra Electric division. There is an updated track chart at the bottom showing current CTC (red) and ABS (green) territories. both 67th St (MP 14) and Kensington (MP 19) interlockings used to be blue, indicating tower control. Express tracks are on the outside, local tracks on the inside serving island platforms. The tracks between 67th St and Kensington was upgraded to bi-directional operation some time ago, but between 67th St and Chicago it remains ABS. Moreover, between Roosevelt Rd and the Randolph St terminal, trains work on sight within unsignaled yard limits with hand operated points.

Back to the tower we head to the top floor where we find a surprisingly large 176-lever GRA Model 5 pistol grip style interlocking machine. While only a small fraction of the levers were in use at the time of its closure, back in the day the tower would have also had control of the 4 parallel freight tracks. Here we have the left side of the machine starting at lever 1.

Tuesday, November 15, 2011

Clear Sweep on the Port Road

For the last few years NS has been "cleaning up" most of the PRR heritage on the Port Road.  Having already eliminated the old PRR pole line 100Hz power supply and embarked on a project to remove most of the old catenary poles, this past week they finally completed work on a project to re-signal most of the old territory controlled by COLA tower.  Back in 2007 I discovered the first part of this project taking place at CP-SHOCKS where the PRR PLs were being replaced with the standard Darth Vader types.  Since then the project spread to CP-LAKE and finally CP-COLA, which was actually still using the original PRR era relay logic from the COLA tower CTC project.

The scope of the project was to install full Rule 261 operation between CP-CRESS and CP-SHOCKS.  While CP-SHOCKS and CP-LAKE were both re-signaled independently and in short order, the COLA and CRESS portion of the project took a little longer to complete with replacement signals standing at COLA since at least July and only being finally cut over in conjunction with the entire line segment between there CP-LAKE.  With the cutover CP-LAKE was removed from service as an interlocking with the third middle siding track between there and COLA being converted to having a hand throw western end.

The desecration didn't stop there as both ends of the Harbor siding were also re-signaled.  This was a 6000 foot, non-signaled siding with slow speed entrance and exit.  CP-WEST HARBOR appeared to have been recently rehabilitated with fresh paint on the eastbound PRR PL mast, but I guess this was just a fakeout as someone made the decision to upgrade both the entrances and exist to Medium speed operation and possibly signal the siding as well.  Fortunately I was able to get pretty good coverage of COLA and WEST HARBOR, but time ran out before I could get to CRESS or the PL intermediate signals between there and COLA.  Fortunately I do have a smattering of coverage from one of my contributors taken in 2006 which I hope to include in a future survey piece. 

In one last bit of news I noticed at MINNICK that along with the catenary poles the Conrail-era 100Hz power supply station was also ripped out, although the PRR PL signals there were given a fresh coat of paint indicating that NS has no plans to fully destroy the southern Port Road branch yet. 

Sunday, November 6, 2011

PRR Main Line Survey 2009 Part 7 (ALTO to CP-UN)

In this Part 7 of my 2009 PRR Main Line Survey I will cover the segment between ALTO and CP-UN.  Now while I did devote an entire special post to ALTO tower, my Main Line survey is not simply going to skip over that part like it was some sort of black hole so we begin again at the east home signal of ALTO tower at the end of the platform of the Altoona Amtrak Station.  Here you can see the applicable track diagram.

Again if anyone is interested in the official interlocking diagrams you
can download them here. ... %20Charts/

You'll want the 1998 Pittsburgh Division one.

ALTO marks the transition from a two track railroad running under Rule 261 on both tracks, to a three track line with single direction Rule 251 on the outer tracks and Rule 261 on the center track.  ALTO was arranged, or possibly re-arranged back in the Penn Central era, to allow easy access for Amtrak trains in both directions to access the station platform(s) located on the north side of the tracks.  The 31 switch allows westbound trains to continue either on the 251 track 3 or the 261 track 2.  Eastbound trains are given a straight shot to the platform off of track 2.  Passenger trains heading east on track 1 must first cross to track #2 at SLOPE.  Anyway here my train departs the Altoona station and takes the #31 switch set reverse to track #3.

Here we see the reverse direction 20R dwarf signal for movements on track 1.  This signal is controlled from the main machine in ALTO tower.  To the right we see the helper pocket track and its eastbound 32R dwarf signal.  The pocket exists between that signal and the PC era signal gantry.

Ironically one of the most iconic structures at ALTO appart from the tower itself wasn't even original to the interlocking.  The 5-track  beam type signal gantry was installed during the Penn Central era in conjunction with a PennDoT bridge and highway project in the area.  The gantry supports three high signal masts governing westbound movements on tracks 1 and 2 as well as the helper pocket which are worked from  levers 2R, 6R and 8R on the main machine.

ALTO tower itself posing by the westbound lattice signal gantry which probably dates from when the tower was built in the early 20th century.  Sometime in 2008 the tower was given a fresh coat of gray paint, but this investment was not a signal of any sort of longevity as you all now know the tower is scheduled to close sometime in the next year.

Here we are looking at the 6 track eastbound gantry at ALTO, which only supports two high signals for tracks 1 and 0.  The slow speed diverging aspects on both are for movements onto the yard leads which are in fact signaled to CP-WORKS as a controlled siding. 

Here we are looking at the 1sw and my extension the entire ALTO facing point ladder which runs from here to the yard leads at the other end of the interlocking.  As ALTO is basically a yard-terminal tower most of its movements involve trains either passing straight through or heading into/out of the yard, hence the ladders that head to that side of the track.  As expected ANTUS interlocking can be considered the reverse of ALTO.

Here we see the eastbound home signals for ALTO on tracks #1 and #2.  As expected the reverse direction track 1 signal is a dwarf and the bi-directional track 2 signal is a mast.  This zoom view provides an interesting prospective on the layout of the entire interlocking.

Saturday, November 5, 2011

Cardinal Dome Car and JC Cabin

First a small bit of good news.  Amtrak is now attaching its great dome car to the Cardinal in the later half of the fall foliage season after the car completes its stint on the Adirondack.  The even better news that unlike the Adirondack the dome on the Cardinal  runs as the last car.  This not only provides better photos forward (as the hot exhaust won't distort the photos), but also a rear facing railfan window, replacing the one that was lost when the Viewliner was moved to the front of the consist in 2010.  So, if there are any C&O signals left in 2012, the dome car trip will be the time to photograph them.

Unfortunately, on a related note it appears that the CSX lease of its C&O Clifton Forge to Orange route to the Buckingham Branch shortline is not enough to preserve all of the classic C&O signals on the line (although it helps).  While looking at pictures from Charlottesville, VA I noticed that JC Cabin, the diamond crossing with NS, is being re-interlocked and with that the old C&O mast signals are being replaced by single head, 4 lamp darth units (albeit with what look like non-Safetran lamp units).  NS signals, which consist of a northbound Southern style cantilever and southbound southern style and NS style lollipop masts, appear to be untouched.  I am assuming the motivation is greater reliability of the interlocking to avoid delaying NS trains.  I will be passing through there next week and will try to get more information.

Sunday, October 30, 2011

It Keeps Getting Worse, HULL N&W CPLs to Fall

Signaling news this year has been an absolute disaster and it's not over yet.  This time one or both of the three track N&W signal bridges at HULL interlocking are being prepped for replacement.  So far only one gantry appears to be under threat, but if this is a full re-signaling then expect both to come down.  For a bit of background this is possibly the only pair of 3-track N&W style CPL signal bridges that exist anywhere.  While common on the PRR, the N&W was always more restrained with its infrastructure and HULL interlocking was one of the few 3x3 crossovers to be found on the system.  The interlocking is located in Iaeger, West Virginia.

NASBY Re-Signaling Update

It appears that whatever NS has planned will involve a new interlocking at MP 293 taking the place of the NYC/Conrail style automatics near Ware Road.  As is common on the western Chicago Line these autos consisted of a Conrail type mast and an NYC type bracket.  The mast supplemented the bracket when the introductions of doublestacks ruined the sight lines.

Unfortunately they are also re-signaling the CP-295 interlocking which in addition to some NYC masts and a bracket, also has a searchlight dwarf stack off the siding.

Tuesday, October 25, 2011

No Surprises on the Cumberland Sub

Well it took less than a year after CSX replaced the CPLs on the Magnolia Cutoff for them to return and finish the job between Orleans Road and Hancock.  While the Cuttoff was known for its use of bracket masts, this section was all about the 3-4 track B&O signal gantries.  Just about the only good news is that all of these signals are accessible by a rough public road built on the empty part of the right of way.  I hope to get out there myself in coming weeks.  Anyway, I was tipped off by photos showing new Darth Vader signals already going up at GRASSHOPPER HOLLOW, which miraculously survived the closure of HANCOCK tower in 2007.

Tuesday, October 18, 2011

C&O Resignaling Marching Up The New River Sub

If you are looking to take an Amtrak trip I might recommend taking advantage of the dome car when it appears on the Cardinal in a week or two because it appears that CSX has really set its sights on re-signaling the New River Sub and its classic C&O signals.  Fortunately I have managed to cover this section twice, but they were hardly under ideal conditions.  I had hoped to get back next year, but I am not sure how much will be there to await me.  Anyway the bad news is that the C&O towns of Prince and Thurmond will soon be sterilized and rendered useless for future generations of railfans so take a road trip out there while you can.

Sunday, October 16, 2011


Known as 16th St Junction or 16th St Crossing, the complex flat junction just south of Chicago's famous loop is the survivor of what used to be a dynamic duo of towers that shepherded some of the nation's flagship passenger trains in and out of downtown Chicago from points easth. Working opposite 16TH ST was the far better known 21ST ST (aka Alton Junction) and its 20 diamonds, but both towers were of such importance that both towers ended up with profile pages on

16TH ST was located at the crossing of the Chicago and Alton route to Saint Louis and the southwest, the Saint Charles Air Line (jointly owned by the Illinois Central and Chicago, Burlington and Quincy) which provided cross-town freight service with the parallel north south Chicago, Rock Island and Pacific and New York Central (Lakeshore and Michigan Southern) main lines into the iconic LaSalle Street Station. Less than a mile to the west was 21ST ST owned and operated by NYC arch enemy Pennsylvania Railroad with smart brick structure with a Union Switch and Signal interlocked pneumatic plant. If back in the day one had asked which tower would still be up and functioning in 2011 one would have surely assumed the PRR plant, as it was nearly 40 years 16th St's junior and made of more durable materials. However not only was 21St ST closed in 2005, it was completely demolished(!) a few years later leaving 16TH ST to soldier on alone.

Today 16TH ST junction is much reduced from its heyday, but it is still complicated enough to protect the tower from any sort of hasty re-signaling scheme. The Chicago commuter rail authority, Metra, owns and operates the tower as part of its Rock Island division. The parallel NYC main was removed in the early 1970s when Amtrak shifted all passenger operations to Union Station. The former Alton route was merged into the GM&O before that merged with the Illinios Central and was eventually absorbed into Canadian National. The Saint Charles Air Line is now owned jointly by UP, BNSF and CNIC and used for various through-routings as well as Amtrak trains accessing the former IC Main Line to downstate Illinois and eventually New Orleans. A diagram of 16TH ST as it appeared in 1931 can be see at the following link.

16TH ST interlocking is not trivially accessible as it is in the middle of a large brownfield area next to the Chicago river, fenced off from the public. The best way to photograph it outside of riding the Railfan Window equipped METRA Gallery Cars is from the adjacent Orange Line that runs between Midway airport and The Loop. Even then you're going to need a good zoom.

Before we begin I would like to mention that the large format photos are not mine and were provided by one of my sources for this and other explanatory essays. Also the full set of non-captioned photos can be viewed here.

Here we see 16Th St from the southeast showing off the plain black on white lettered nameplate and the operator's parking lot. In the background we can see Roosevelt Ave which provides a popular photo location at the mouth of Chicago Union Station across the river.

As the Orange Line crosses the Rock Island division tracks we see the 68/69 trailing crossover and the 56 switch which forms a wye connection to the Air Line. That connection contains one of the interlocking's more unique features in the form of a diamond crossing over track 2 due to the originally constrained space creating too tight an angle for the track to connect in the usual fashion.

Here we see the tower end on with the CTA Red Line emerging from the downtown tunnel just past the former Alton tracks.

Finally we have a nice high res closeup of the east side of the tower and yeah...its a handyman's dream. Compared with the 1958 pics on you can see that the siding dates from at least that time. The tower has developed a bit of a sag and half the windows are boarded up internally. Just about the only thing that isn't patched and falling apart is the roof, which was clearly replaced recently. The ladder is some sort of fire code thing, although I don't see how anyone could ever access it. I would not expect this tower to be preserved or to live on much past its eventual closure. It is too small to make a useful C&S/MoW base and its structural integrity probably leaves much to be desired. Also in urban environments towers like these tend to catch fire after being closed although this one standard a good chance of going up even before then.

Here is a diagram of how the interlocking appeared in 1931 with the combined New York Central/Rock Island 4-track trunk line crossing the St. Charles Air Line and Illinois Central lines with assorted connecting tracks.  The GRS model 2 machine was far less advanced than the US&S equivalents, which relied more on electric logic. As such points are not worked in pairs so a crossover requires two lever slots (although one lever is a phantom internally slaved to the first). Furthermore signal head gets its own lever and combined with traffic levers for the diamond crossings and lock levers for who knows what one can see why the machine has over 150 total levers.