Dispatcher Signal Stacking

The story of railway signaling, like many others, has been one of technology increasing human productivity. Power operation allowed "levers" to be thrown faster, N-X machines allowed routes to be set with fewer button presses and remote operation combined with CTC allowed one person to control many miles of track. However remote control and ease of operation were not the only types of automation added to towers and dispatch offices. Fleeting allowed infrequently manipulated interlockings to do the same thing over and over and in cases where routing decisions needed to be made, automatic route setting combined with train labeling could keep track of train movements and automatically request routes as they approached junction points.

Recently another method of automation has crept into dispatch software, route stacking. While similar to automatic route setting, it is different in a significant way. Consider the following pair of photos showing an Amtrak Springfield shuttle train departing SPRING interlocking at Springfield Union Station.  

 

Within seconds of clearing the interlocking the 2N dwarf signal (upper right of the photo) changes from Stop to Restricting for an opposing movement. In the past this would signify a very attentive dispatcher, hovering over their CTC panel or video display, ready to line the new route as soon as possible. If this was an auto-routing system we would have had to wait for the opposing movement  to enter the track segment to trigger the route request.  With stacking the dispatcher simply uses their computerized dispatching interface to queue up a sequence of routes which will be executed as soon as the last established route is taken. Then they can do and pay attention to something else.  

This works well at places like Springfield where reverse movements are common. For a northbound train the dispatcher could set up a route from the 2S at SWEENEY, 12 switch reverse. Then immediately have a second route set for the 1N 13 switch reverse to the CT River Main Line.  It's not super complicated, but it is something that, due to the time penalties associated with bad routes, took a little while to catch on.

NAN Drawbridge: A Crazy Thing We Lost

While this is ostensibly a blog about railroad signaling, I'll sometimes cover related bits of historic technology like railroad telecom systems, electrification systems and drawbridges. Today I get to cover two of those topics at once. Located on the former New Haven Railroad Shore Line, the Niantic River Drawbridge sat at the mouth of the Niantic River in the town of, you guessed it, Niantic, CT. A former New Haven Railroad signaling station, the 1907 bridge would later take the name NAN in the Penn Central and would serve as a staffed interlocking and block station up until the Boston electrification project of the late 1990's. Due to the New Haven being in perpetual bankruptcy NAN saw little in the way of upgrades and was documented by the Library of Congress before the changes of the NEC Improvement Project. While a chain-driven rolling lift bascule bridge is pretty cool in and of itself, it was the electrification project that provided "Old Nan" with one heck of a curtain call.

Railroad movable bridges have to employ complex mechanisms to separate the running rails and unlock the bridge, however when overhead electrification is involved a separate yet equally important system to isolate the contact wire across the movable span must also be employed. Because the 1907 NAN bridge was not electrified for its first 93 years of existence, this system had to be retrofitted onto the rolling bascule span in situ.  

On the contemporary Pellham Bay bridge, which was electrified within a decade of construction, a mechanism isolates the dynamic tension contact wires, while an alternate routing takes the 12kv lines up and over the waterway. The span then rolls back causing the wires across it to sag down to touch the track structure.  (I have seen a photo of this, but cannot currently locate it.) However when NAN was electrified in the 1990's, Amtrak had to use a fancy constant tension solution and in this case that meant a solid aluminum rail type conductor running the length of the span. Now, if you're sharp you might already realize that when the bascule span rolls back, a solid rail can't bend and flex with it. Well, this video shows the solution.  

That's right, a traveling telescoping carriage would move back and forth to extend and withdraw the contact rails from below the rolling structure of the bridge. What's even crazier was that NAN was the busiest drawbridge on the NEC due to a low clearance of 11 feet and a steady stream of boat traffic. Due to complaints from boaters, an agreement with the Coast Guard in 2003 limited closings to "only" 48 per day, so in its final decade of service, Old Nan was putting on quite the show. Unfortunately the 1907 bridge was finally replaced in 2012 by a new bascule span with greater clearance to reduce the need for openings. Fortunately its presence in plain view right downtown allowed for many to personally experience the show and record it for posterity. 

 

More Connecticut River Corridor News

 Although my last update on the Connecticut Valley Corridor was only back in March, I have some additional updates from a follow up trip in October. The most significant are alterations to SPRING interlocking in Springfield, MA. The root cause for altering SPRING is to create an interlocked connection between Boston Line Track 2A and the Amtrak Springfield Line trackage. This route was previously used by the old Vermonter and Inland Route Regionals and required the use of hand throw switches to the east of the station. Without a connection at SPRING, Track 2A is only purpose is to serve as an emergency berth for the daily Lake Shore Limited round trip. The new switch allows Track 2A to be used for both CT Rail Hartford Line trains and Amtrak Springfield Shuttles and also creates additional storage space for increased CT Rail or Regional service. 

Of course there always has to be a downside and unfortunately the changes at SPRING will also cause the elimination of what is arguably the last vintage signal on the Amtrak Springfield Line.  Station track #8 is still governed by a US&S N-2 dwarf, possibly dating back to the New Haven era.  Moreover station track #6 is governed by an uncommon US&S modular dwarf stack that was installed in the early-2000's to replace an H-5 searchlight.  Both will be replaced by Safetran modular cube dwarfs that infected the Springfield line back in 2004.

The bad news doesn't stop there as the New Englande Central re-signaling project continues unabated. It currently appears that new standard sized ABS blocks are in service between Walpole and Claremont, replacing the old B&M large block CTC. This also implies that the new signaling at Claremont has been activated. New interlocking huts have been dropped at both the south end of the Walpole siding and the Bellows Falls diamond. At the north end of the Walpole siding the new interlocking retained the southbound searchlight mast, so it remains to be see if there are any searchlit survivors in the Bellows Falls area. I unfortunately neglected to inspect the controlled point south of Bellows Falls, but it is on my list for a visit in the Spring.

Metro-North to Penn Station Threatens Rare Amber PL's

 Because of the unsustainable drive to create one seat rides, The State of NY has been eyeing sending New Haven Line Metro North trains over Amtrak's Hell Gate Line to Penn Station.  If it were this simple I probably wouldn't be writing this post, but as part of it the state is looking to completely rebuild the line with 4 new stations and 6 new or rebuilt interlockings.  This would likely not only mean the end of the existing amber position lights, but also any wayside automatic signals and possibly all position lights to better match the new color light signals in the East Side Access Zone. 

The plan can be located at:

https://static1.squarespace.com/static/5d278d57950ce60001fd9b83/t/60a431e43e998f0fd9e0004d/1621373417555/02_PSA+EA_Project+Alternatives.pdf

With a web formatted version posted here.

http://www.subchat.com/read.asp?Id=1576330

The key features are the new track layouts and interlockings that will do much to restore the former 4-6 track passenger and freight corridor.  Instead of just installing platforms along the existing two track line that sees at most 4 Amtrak trains per hour, New York would install a new pair of center placed tracks for stopping trains.  

 

 Hopefully a conservative backlash to funding Blue State megaprojects will keep the Hell Gate Line signaling intact for another couple of decades.  Until then make sure you try and document it as best as possible, even though the only real way to get photos is to spring for Regional business class.

MBTA Cab Signal Project to Include All South side Lines

I previously reported on the Rule 562 cab signaling project on the Boston Line that extended the cab signaling from CP-21 in Framingham to the Amtrak division post at COVE.  It now appears that the need to install cab signaling for the ACSES PTC system is resulting in the same treatment being given to the Needham and Franklin Lines.

NEED Interlocking eastbound mast.

As we saw with the Boston Line, existing interlockings are being left unaltered, except for the addition of Rule 280a "Clear to Next Interlocking" lamps, as seen here at NEED interlocking on the Needham Branch during the summer of 2019.

New Franklin Line interlocking in Norfolk, MA

 An exception to this is on the Franklin Branch where several additional miles of double track are being added with the eventual goal of the double track extending all the way to Franklin/Dean College.  This is resulting in new interlockings with new cantilevers and new Safetran scallop shells arranged in a target formation.

Franklin Line Signal 284.

Most of the signals appear to be legitimate GRS G-Head signals, installed in the 1980's to replace the original New Haven signaling although the Franklin Branch will also be losing searchlight intermediates at mileposts 11.7 and 13.1.  Additional color light signal locations presumably being lost are mileposts 16.9, 22.1, 23.5, 25.9 and 28.4 on the Franklin Branch and mileposts 7.1, 9.6 and 10.6 on the Needham Branch.

Franklin Line signal 302

Uncertain are the 12.6 and 12.7 automatics around Needham Center and the 302 automatic at the Forge Park/495 Franklin Branch station where terminal operations make wayside signals somewhat useful.  As of Aug 2019, the holdout signal at CP-HEIGHTS on the Needham Branch did not have a 'C' board mounted.

Stoughton Branch CP-PORTER

Needless to say this should not have come as any surprise.  Not only were all three of the 90's/2000's Old Colony Lines built with complete Rule 562 signaling, but the short Stoughton Branch off the Amtrak Main Line at Canton Junction was 562 as well.  Moreover, the Dorchester Branch, cab signaled in the 80's during its time as Amtrak's route into Boston during the Southwest Corridor rebuild, lost its famous rectangular signals during a late ~2000 562 re-signaling project.  Ironically, this leaves Amtrak's Shore Line, the one with 150mph speeds and ACSES installed since 2000, as the only south side MBTA route to retain its intermediate signals.

PHOTOS: SS44 BERK (and the SoNoToMo)

The South Norwalk Tower Museum comprises the old New Haven Railroad's SS44 (aka BERK) tower in South Norwalk (SoNo) , CT (map) preserved the way it was when it was closed around 1986.

The former New Haven RR main line is operated by Metro North Commuter Railroad, which, unlike is sister Long Island Railroad (this is also operated under the umbrella Metropolitan Transportation Authority), chose to ruin two of the most interesting stretches of classic signaling in the country by replacing forests of searchlights on overhead gantries with a waysideless CSS with 3-aspect dwarf signals at interlockings.

Ironically Metro North did a fairly good job of preserving all of the closed interlocking towers. One of these, SS44 in South Norwalk, was of the brick walled mechanical variety and after being boarded up was eventually sold to a preservation group in the mid-90's who painstakingly restored the tower as a museum. It is probably the only preserved tower with a substantial mechanical lever frame in North America, and a must visit for signal enthusiast visiting the New York City area. Here is a front view of SS44 taken from a passing train.

The museum makes most of its money be selling a truly excellent book about itself, so if you want any further information put and order in and help support the museum.

Signaling Station #44 was built around in 1896 before the "classic style" New Haven tower design came into effect with the pioneering overhead AC electrification project of 1906 and second phase of 1918. These later towers are square, cast concrete with or without brick and a hipped tile roof. Here are some examples.

SS22 SHELL

SS26 PIKE

SS28 GREEN

In 1919 the decision was made to upgrade the original interlocking plant at SS44 to support modern interlocking technologies such as electrically operated signals, track circuits, etc instead of attempting to build a new tower.  Despite the attrition of the early 20th century upgrade program  SS44 does still have a surviving sister by ways of SS214 HART in Hartford, CT.  Unfortunately HART was not as well preserved having suffered a fire and is now threatened by demolition.

While the square footprint NH "standard" towers were designed to take all power frames or electro-mechanical frames with lever operated points and miniature lever operated signals, the narrow rectangular SS44 had a 68 lever all mechanical frame made by the Johnson signal corporation. A more accurate term for this frame might be electro-enhanced mechanical as like later E-M frames, like the US&S style S, all the signals are power operated and governed by both track relay logic and mechanical interlocking logic. The frame was well organized with the red signal levers placed at either end sandwiching the blue and black point and FPL levers. All signal for eastward moves were on the west side of the frame and westward moves were on the east side of the frame.

The lever frame has been fully restored and disconnected from the electric-locking so that one can fully exercise the mechanical locking setting up routes and displaying signals. Unlike British practice all of the points are equipped with facing point locks because trains could operate against the current of traffic under train orders on a fairly regular basis. There almost seem to be more locks than point levers!

New Haven Railroad Miniature Suspended Semaphores

Perhaps the oddest semaphore signals ever see in North America were those in the New Haven Railroads electrified district. 3-position electrically driven semaphores were mounted on the overhead electrification cross supports. Due to the complexity of the catenary obstructing the view of any signal mounted above the gantries, they were suspended down between the tracks with a stub semaphore blade as to not obstruct the loading gauge. The motors for the blades were mounted on top of the gantries and drove the blades via long connecting rods

All of these signals which had not been converted to US&S H-5 searchlights were removed in the early 1990's and replaced with nothing as Metro North went to an all cab signaling based system. I bring this up because some wonderful person posted a mess of photos of these signals, something I have never seen before, so I have decided to give them some exposure here.

Our first batch of  suspended semaphores have the rounded end, normally used for Train Order signals, but in this case I am not sure of of its significance, although from context I can assume it is a type of absolute signal.  These signals were installed in a 2+2 ABS 251 configuration and we can see come bagged H-5 units for the coming 261 operation on all 4 tracks.  Also note the H-5 on the read of the closest semaphore.

Here is a closeup of that nearest signal this time displaying an Approach Medium (Y/G) indication.  The New Haven RR used Y/Y for Advance Approach instead of either Y/G or *Y*.