Interlocking Preview: PLAZA

As we continue to march along in our alphabetical tour of the LIRR's various interlockings, today we stumble upon our second Interlocking Preview.  PLAZA interlocking is the first of the two new interlockings that are being constructed as a part of the East Side Access project.

In May I gave you my best guess as to what ESA interlocking would possibly look like.  ESA would  be the interlocking that encompasses all the switches on the Manhattan side of things--taking trains from the two tunnel tracks and sending them into the eight different station tracks.

PLAZA interlocking would be on the Queens side of the East River.  Squeezed uncomfortably between Queensboro Plaza and Queens Plaza subway stations, the interlocking will take trains that come off the LIRR Mainline and Port Washington Branche at HAROLD interlocking and funnel them into the two tunnel tracks under the East River for their trip to the depths of Grand Central Terminal.

The layout and design of PLAZA interlocking has likely changed about four thousand times since the plans were originally drawn up, and between now and opening day of ESA, I bet it will change a couple times more.  So this is my best guess as to what the interlocking might look like.

Nonetheless, here it is (and here's a bird's eye view of the location):

PLAZA interlocking itself is quite simple, its pretty much just the stuff pictured in the lower diagram.  The four Queens soft-bored tunnels come out and merge into two tracks to go under the East River, there's a pair of crossovers, and we say goodbye to daylight until we come up the escalators at Grand Central.

However, the far more interesting and complex bit of PLAZA interlocking is the five tubes that radiate out from the Q-tip into different strategic points in HAROLD interlocking, where they merge into the LIRR mainline to go off to their various eastern destinations.

So let's start from the top.  We'll go from east to west this time instead of the usual left-to-right reading of these walkthorughs.

Beginning at the eastern entrance to the busy HAROLD interlocking, the trains will come off either the LIRR Mainline from Jamaica or the Port Washington Branch.  From there there is a set of switches and crossovers that serve to shift the many trains towards their proper tunnel or yard entrances.

So there are four revenue Queens tunnels, two on the very north and south edges of HAROLD (for westbound and eastbound trains, respectively).  We'll deem the two outer tubes tunnels A and C.

Then there are two more tunnels that poke up in the middle of the interlocking.  The LIRR is quite fond of having things sneakily come up in the middle of interlockings (it is what makes Jamaica work so well, after all).  Those two tunnels can service trains going in either direction.  We'll call those two tunnels B and D.   Now in normal operations, tunnel B will primarily serve westbound trains and tunnel D will primarily serve eastbound trains, but during rush hours both tunnels could be used in the peak direction to speed things up and add capacity (especially in the morning). 

Tunnels B and D pop up in HAROLD right near Switch 813.  You may remember that in the summer of 2012 this particular switch was out of service for several weeks for ESA work (and thus causing a handful of trains to be canceled and combined--just like what happened this summer).

And speaking of the Westbound Bypass, I tried my best to guess where it would go when it is all done on the above diagram.  I haven't a clue where it will actually go, and the satelite photos are too out-dated to give me a clear idea of where it will be leading, but that is my general guess on how the thing will work.  The Eastbound Bypass is also pictured.

Back to the LIRR, the four different tunnels will go just under the surface (not all that deep at all) and they will curve slightly to the north where they will go underneath all the other tracks in HAROLD and Sunnyside Yard.

View of the Q-tip from space.

From there we shift down to the second diagram above.  Shortly after passing underneath the northwesternmost track in Sunnyside Yard, the tracks emerge from their tunnels for a few brief moments.  This little area, nicknamed the Q-tip because of how it is shaped, was the primary launch site for all of the Queens-side tunnel boring machines.

From here, machines bored tunnels to the 63rd Street Tunnel portal and to the five opening points in HAROLD as mentioned above.

I'm unsure if the LIRR plans to leave the Q-tip open as it currently is now.  Thinking back to the depths of my mind, I've head conflicting stories on what the LIRR plans to do with the Q-tip, but most of that will probably go out the window as work moves along anyways.  I guess we'll just have to wait and see.

There is also one more tunnel that I didn't mention above: the yard lead tunnel.  The Yard Lead tunnel will most likely split off from tunnel A at some point and it will tie into the Sunnyside Loop.  Currently, Sunnyside Yard is used exclusively by NJTransit and Amtrak, but once ESA opens, they'll make some room for a handful of LIRR trains that will spend the day there in-between runs into and out of Grand Central.  How many trains the LIRR can realistically store here is yet to be seen, but the LIRR is going to need some hideouts for its trains since the Grand Central terminal will not have any yard space at all.

There is only going to be one yard lead track on the southern end of the loop.  Since all of the LIRR's trains are push-pull capable and can be operated in either direction, there is no reason to have an additional exit on the other side of the yard.  Not to mention the LIRR hates having its electric trains looped or wyed or anything that physically tuns them around.

So that's about it, folks.  Be sure to take a good look at that top diagram above...I tried to make it depict things as clearly as possible (it is much easier to understand than it would be if I just sat here and typed 15 paragraphs about every little switch.)

I honestly am not sure as to who will have control over what sections of tracks that are part of the ESA project.  I can pretty much assure you that everything that touches HAROLD interlocking will be controlled by Penn Station Central Control (PSCC).  Beyond that, I can't be sure.  Part of me says it will be the Section A dispatcher in Jamaica, but part of me says that PSCC will do the honors just to keep all the western terminals and the like in the area all tied together.  After all, movements out of LIC and HPA are governed by PSCC if I'm not mistaken, but it's far to early to tell what's going to be the deal with ESA.

As the project nears completion, I'll come back and take a look at HAROLD, PLAZA, and ESA interlockings to see how they have changed since we last visited them.  Just like any ongoing project, changes to the plans are probably made a couple times a day, so it is very difficult to nail down an exact idea of what's going on--especially when you're outside the loop like I am.  But nonetheless, the above post is my "best guess" and we'll return to the land of present-day interlockings that exist next week when we take a look at PORT interlocking.