Interlocking Walkthrough: BROOK

This week's interlocking through covers BROOK interlocking, in Brooklyn, and by Brooklyn I mean the LIRR's "other" western terminal--Atlantic Terminal.  This interlocking is unique to the LIRR in the sense that it is the only interlocking that is underground.  (Yes, Penn Station's interlockings are underground, but those aren't LIRR interlockings, they're Amtrak ones.).  And because it's underground, getting a bird's eye view of it on Bing Maps just ain't gonna happen, but here's a look at the general area for good measure.

For those of us without x-ray vision, here's a diagram of what's going on under the streets at BROOK interlocking:

As you might be able to tell looking at the diagram, this is the first interlocking we meet that is split up.  BROOK interlocking as we know it is actually has two separate limits, there's BROOK 1 and BROOK 2.  More on this separation later.


Switches
Coming west FROM Jamaica TO Brooklyn, the first BROOK we encounter is BROOK 2.  The first switch we see is from Atlantic Branch 1 (the westbound track) to Atlantic Branch 2 (the eastbound track).  This switch is in place so that a train from either track can take the next switch, which diverges off from Atlantic 2 to VD yard.  (more on VD yard later).   Then the set of crossovers is completed with a switch back from Atlantic 2 to Atlantic 1.  At that point, BROOK 2 ends.

When trains first started rolling into Atlantic Terminal (then called Flatbush Avenue) BROOK 2 was actually called VAN interlocking (short for Vanderbilt).  However, when VAN tower was closed down many, many years ago, all the switches and signals were remoted to BROOK tower just to the west.  At that point VAN was renamed to BROOK 2 (and the original BROOK had a 1 slapped onto it), thus BROOK 2 and BROOK 1 came to be.

Back to the present-day, we go a bit further west (this is all still within the Flatbush Tunnel by the way) and the speed limit drops down from 45 m.p.h. to a snail's crawl at 5 m.p.h.

Next we encounter BROOK 1 which is a simple pair of crossovers, from Atlantic 1 to Atlantic 2, then back to Atlantic 1.  Then there are seven switches splitting out from Atlantic 1 and Atlantic 2 to the six station platforms.  (NOTE: the western limits of BROOK 1 are the actual ends of the station platforms, when I was arranging the diagram earlier in the week I must've put that western line in the wrong place--I have since corrected it).  All 7 of those switches are part of BROOK 1, those switches let the two Atlantic Branch tracks diverge off to the six station tracks.  It's worth noting that station track 6 can only handle four cars, and it's right up against the subway tracks at that location.

The switch at the eastern end of station track 3 is what's called a "double slip switch" that allows a train to go from station track 4 directly across to Atlantic 1 without having to shuffle back and forth over two different switches.


Now BROOK interlocking also contains VD Yard.  VD is short for Vanderbilt Avenue which is nearby in Brooklyn.  VD yard is currently a bit of a mystery (to me at least).  Ever since the construction of the Barclays Center began, VD yard has been reconfigured a bunch of times and I am currently unsure of it's current layout.  The diagram above shows how the tracks looked in 2009, but I'm not sure if they're set up that way today (my guess is no).

Anyways, VD yard was always kinda strange.  The way it is set up requires a train coming from the yard and going to the station to do a reverse move in the tunnel.  So the train would pull east out of the yard, onto Atlantic 2 or Atlantic 1, change ends, then pull into the station.  The yard existed outside of the Flatbush Tunnel, so that part itself is not underground, but the yard might have since been overbuilt by the arena.  I will be making a field trip to that area sometime tomorrow to check out what it's like in person then I'll report back over the weekend.

It is also worth noting that VD yard is only used on weekdays.  The yard lays empty all weekend long as all of the trains to go west into Atlantic Terminal go straight back east again.

Signals
BROOK interlocking uses a unique type of signal to suit its needs.  Because BROOK interlocking is crammed in the very narrow and short Flatbush Tunnel, full blown position light signals wouldn't fit here.  So instead the LIRR uses an older-style colored light signals that look like they've been there for quite a while (these are not the newer LED color signals seen at places like AMITYVILLE interlocking), these are older, incandescent bulb signals on more compact fixtures on the sides of the tunnels.   These signals are also seen at some other locations within the Atlantic Avenue/Flatbush tunnels, but most of them are concentrated here.

Towers
BROOK interlocking is still home to a real-live LIRR Tower (one of the very few left).  BROOK tower is located at the very end of the station, just south of Atlantic Branch track 2.

Neighbors
BROOK has no neighbors to the west, the Atlantic Branch ends right here at some bumper blocks.  To the east, however, ENY by East New York station offers the next opportunity to switch tracks.

That wraps this week's interlocking walkthrough up.  A special post on the LIRR's "other" terminal and how the LIRR should be using it more is in the works, and you can expect that sometime next week.  For now, however, we wait until next week's Interlocking Walkthrough episode: CI in Central Islip.