July 2014 Union Strike

A tentative deal between the MTA and LIRR Unions to avert a July Strike has been reached. See this post for more information.

Wednesday, August 28

Interlocking Walkthrough: PD

PD interlocking, on the scenic and delay-plagued Montauk Branch, spans the immediate area around Patchogue station.  Located roughly 54 miles away from Long Island City, the interlocking has been at this location since the early 1910's.  While it has undergone some changes in the past decade, the switch setup is still very similar to what it was "back in the day."

Below is the diagram of the switches that make up the interlocking.  As of 2006, the interlocking has been split up into three separate sections PD 1 through PD 3, but the diagram shows it all as one big PD interlocking.

The origin of the name PD has a bit of history behind it.  Originally PD tower was constructed at its original location to help protect the tracks at the location where it was crossed by Suffolk Traction Company streetcars that were bound for PatchogueDock.  Suffolk Traction Company was a streetcar system that began service in 1909.  It was a short trolly line that ran between Patchogue and Holtsville.  When operations ceased in 1919, the tower remained into the 21st century as a switch tower for the LIRR.

The interlocking itself today basically consists of one big passing siding.  The interlocking begins just to the west of Clare Rose Boulevard.  Between that crossing and the station platform the North Track splits off from the Montauk Branch and runs north of the station track.

Patchogue station only has one side platform, one that is a mere six cars long and sits on the south side of the tracks.  Trains that go onto or off of the side trac
PD with new and old signals during the
signal replacement project.
(Photo credit: Trains Are Fun.com)
k cannot access the platform, which adds to the clumsiness of moves that involve the siding.

There is also a Fence Track that splits off from the siding in between South Ocean and Rider Avenues.  That track had a better use back in the day of steam locomotives, but in today's system of cab-cars and push-pull locomotives, the short track sits largely unused.

A handful of trains over the course of the week are scheduled to use this track.  The siding is primarily used by shorter scoots that terminate at Patchogue.  After making their final stop at Patchogue, they'll pull east and back into the siding (or back west and go right into the siding) to get out of the way of through trains that are going to either Speonk or Montauk.

This area is infested with grade crossings (especially to the east of here).  Between MP 52 and MP 55 there are no less than 12 grade crossings.  Because of this, the speed limit is comparatively low through the area--40 mph.

The new signals at the interlocking next to the former
PD tower.  (Photo credit: Trains Are Fun.com)
For the longest time this interlocking had a tower that stood on the grounds.  In 1970 all the switches at PD were automated, but the tower still remained there and in service until 2006.  Due to deteriorating structural conditions, the tower was taken out of service on May 8, 2006.  The tower was later torn down on August 22, 2006.

PD tower has a bit of a story behind it...but I'll save that story for a special post that will appear on Friday.

Before PD's closure in 2006 the entire interlocking was renovated.  The older position light signals were replaced with tri-color aspects and all the switches received
new mechanisms.

Be on the lookout for that special post on PD tower Friday!


  1. Isn't there a crossover just east of Ocean Ave from the main to the north side track? I see it in a few of the pictures. Or was it removed?

    1. Yes, there is still a crossover there. It was accidentally left out of the diagram above and subsequently the explanation below. As soon as I get Adobe Illustrator installed on my new laptop I'll make the fix.

      Thanks for noticing,
      ~ Patrick @ The LIRR Today


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