MBTA Putting Cab Signals w/o Waysides on Guilford Main Line

 I had previously reported on the conversion of at least some North Side MBTA lines to a system of cab signals without wayside signals as part of the ACSES PTC project.  However for some time the Guilford Rail System had been resisting this as they were not required to install PTC and they did also not utilize cab signals on their system.  Therefore imagine my surprise when I discovered that the Guilford Freight Main Line between CPY-WF and the end of passenger service at Wachusett.  

 

Technically the portion west of CPF-AY in Ayer is part of the NS Pan Am Southern joint venture and with CSX still trying to purchase the Guilford, two cab signal users would dismember the Guilford and would have equipped locomotives available to lead on the freight main line.  Still, dealing with cab signal islands is a major headache and it is further puzzling that waysideless cab signals (NORAC Rule 562) would be the preferred method between the back-to-back  CPF-AY and CPF-WF where the MBTA trains exit towards Boston.  Perhaps the plan is to be able to dive NORAC Rule 280a, Clear to Next Interlocking, bor unequipped movements. 

 

Regardless, we have seen with SEPTA that it seems easier to equip two types of PTC systems than mixing trains equipped and unequipped with cab signals.  CSX literally SEPTA-rated itself from SEPTA to avoid a situation similar to what the Guilford is acquiescing to. The good news is that Guilford style signals including target heads and bracket masts are being used in this project.  Unfortunately it is likely that fairly new Guilford intermediates with offset heads and double green clear indications may be removed prematurely. 

In an interesting turn of events, Guilford or the MBTA have decided to spring for genuine US&S NR-1 target type signal heads instead of an off brand modular approach. No way CSX or any other potential owner would do such a thing.

Conrail Tower Videos

 Despite the algorithm Youtube's discovery system is still pretty spotty so I wanted to share a few videos I found showing the operation of some Conrail towers in Ohio.  Unfortunately the first two suffer from a common ailment of interlocking towers videos, near total focus on trains passing by the towers instead of the tower operations themselves.  Of course it's better than nothing and it's great rail videographers were able get what they did, but ultimately locomotives are generally working the same way they did back in the 1960's and will continue to work that way for the foreseeable future. Interlocking towers on the other hand are practically a completely lost art with very little video documentation of how they functioned.

Here in the first video we see inside of the rather large and complex STANLEY tower south of Toledo, OH in 1995.  STANLEY was equipped with a 1930's vintage GRS Model 2 pistol grip frame.  We see one route being lined around time index 4:40 and two more routes being lines around 6:02.  The important thing to watch are the black switch levers stopping before full travel while the points complete their throw and then the lockout lights illuminating when a red signal lever is reversed to line up a route.STANLEY was open using its original machine until about 2015.

In another 1995 we get inside the late, great IU tower just east of Indianapolis Union Station.  Equipped with a 100+ lever US&S Model 14 machine, the tower was closed at some point and re-interlocked, but not re-signaled until just a few years ago.  The tower also contained unit lever CTC desks for area interlockings and retained some degree of functionality until CSX completely re-signaled the plant.  In this video we see only a few brief glances of the operator's floor starting around time index 2:41.  The Model 14 is still present, but it is not clear if it is still in operation.

Since DELRAY tower closed on November 20th, 2020 as the last armstrong style mechanical lever frame in North America, a local railfan posted a video tour of the inside, but unfortunately was not able to capture the machine being operated to line up any train movements.

Finally this news piece from 1986 shows the closure of MORGAN TOWER in Quincy, OH.  This mechanical tower was in service on the Big Four main line complete with power operated semaphore signals. This video does capture a degree of lever frame and pipeline operation as well as some shots of the semaphores rising and falling. Enjoy!

Line of Sight - DART's Third Method

Last year ago I wrote an article on how the DART light rail system in Dallas used two distinct signaling methods.  Automatic Block Signals with Automatic Train Stop  were used on the original Red and Blue lines built in the 1990's and audio frequency Cab Signals without intermediate wayside signals on the Green and Orange lines built since 2000.  However there is a third method first used on the initial segments and most recently employed on the Blue Line extension to Rowlett. This method is Line of Sight operation and while I had seen the signs, I did not fully learn what it signified until I recently had the opportunity to ride the southern portions of the Red and Blue lines that make the most use of Line of Sight.

Line of Sight territory is exactly what it says on the tin.  Trains must proceed able to stop short of any obstruction including other LRV's, pedestrians, motor vehicles, traffic lights, etc.  It is governed by the following section in the DART rulebook.

Line-of-Sight Operation: 

4120 Line - of -Sight Territory Incorporates mainline tracks not protected by ABS/CST. Line-of-sight territory incorporates the following:

• West Oak Cliff Branch - Zoo Station to end of line at Westmoreland Station.
  
  
• South Oak Cliff Branch - Morrell Station to end of line at Ledbetter Station. - Central Business District - Houston Street to Pearl Station.
  
  
• Rowlett - Signal G1813 to Rowlett Station 

4121 Line of Sight Speed Trains must operate at a speed which will enable the train operator to stop short of any obstruction. All special instructions or posted speed zones must be complied with. Speed shall be reduced when adverse operating conditions exist, (i.e.) poor weather. 

4122 Minimum Separation Trains must maintain a minimum separation of at least two LRV lengths unless authorized by the controller or when a train is stored in the tail track. a. No more than one train at a time in the same direction may occupy a city block in the CBD unless authorized by the controller.

When I first encountered Line of Sight Operation at the Garland station on the Blue Line it was accompanied by a two aspect signal that I surmised was part of a low cost go/no-go ABS signaling system.  From the overhead and street view I could identify other signal signals along the line and it seemed that LRV's would approach each prepared to stop within Line of Sight.

It turns out I was only partly correct as these Block Indication signals have their own alternate method of operation. On the two southern routes, Block Indicator signals can work in conjunction with Start Block (SB) and End Block (EB) signs.  Passing Block Indicator with an SB triangle the train is protected by track circuit block until the following EB triangle. I am not entirely sure if the SB is needed before any EB, but that seems to be how it was set up.

The Block Indicators are used where there are line of sight issues like curves and steep overpasses so that LRV's don't have to crawl on these stretches of track.  On the straight and level trains are able to travel on line of sight up to a speed of 45mph. This is of course quite safe as the LRV's are designed to run in traffic and have magnetic track brakes for bus like stopping. When exiting the ABS territory that proceed the Line of Sight territory LRV's receive an "Approach" class indication before the LoS territory sign.

SEPTA two aspect block signals on the Route 102

The DART Line of Sight system is similar to the two aspect signals used on SEPTA's Routes 101 and 102 suburban trolleys, although in that case the signals partly work as a more formal two aspect ABS system. DART Line of Sight allows higher speeds on stretches of track located on median rights of way or city streets governed by traffic signals.  It is worth noting that at least at the time of writing DART trains are scheduled such that only one LRV is expected to be in any LoS section at a time. For example a Red Line train departing Westmoreland is scheduled to enter ABS territory in 11 minutes and the maximum headway is 15 minutes. 

DART's Line of Sight system is a safe and innovative way to achieve cost reductions and enable Light Rail style in street or street adjacent operation with traffic and other non-interlocked signaling. Thanks to the straight jacket of PTC, non-FRA regulated light rail systems are the only place that are able to employ outside the box signaling and safety solutions.

Philly Area Interlocking Updates

 I have two items of interest from the Philly area.  First, new signal masts are up at SEPTA's ARSENAL interlocking covering the new crossover and turnback south of the University City station.  While not directly replacing the LED PRR position lights on the signal bridge at ARSENAL proper, the masts are arranged for the reduced aspect Rule 562 signals despite both the Airport Line and West Chester Line being outfitted for Rule 261 with waysides.  I'm still not 100% sure what the final configuration will be, but it doesn't look good :-(

In other news a recent photo from PAOLI shows substantial modifications to the 4-track full crossover that was made largely redundant by the conversion of the Paoli Station from side platforms to a central island. It also appears that the west end pneumatic point machines have been converted to electric. Here is a diagram of what remains.