Most Brooklyn-bound straphangers traveling over the Manhattan Bridge are familiar with the moment when the sweeping view of the East River is replaced by the darkness of a tunnel as the train descends back underground and, almost like clockwork, stops and enters the tunnel remains standing before entering the tunnel. The Kalb station.
The delays happen often enough and are more notable when they don’t — and the MTA’s schedulers, signal officers and train crews all know that travel on the B, D, N, Q and R trains is slower through the series of well-known switches and tracks. as the DeKalb lock.
But now, armed with new rail cars, new signaling systems — and hopefully billions of dollars with which to buy more of both — the MTA says there is relief on the horizon for one of the most stubborn parts of the subway system.
“Not everyone knows the name of it, but every Brooklyn rider knows the effects of the DeKalb interlocking,” said Jamie Torres-Springer, MTA’s construction and development boss, during a recent visit to DeKalb. “You have 350,000 passengers on these five lines every day, and almost all of them seem to experience a delay of a few seconds or more if a train is stuck on the bridge or in the tunnel, waiting for another train to cross in front of you. of it.”
Simply put, the series of switches around the DeKalb Ave station. switches trains between Manhattan’s Sixth Avenue Line – the orange B and D trains on a typical subway map – and Broadway Line – the yellow dotted N, Q and R – and recombines them to form the D train with the N and R along Fourth Avenue in Brooklyn, and the B with the Q along the Brighton Line in Brooklyn.
This practice, called interlining, gives passengers the opportunity to travel to more parts of the city without transferring to a train. But it also means transit workers must act like air traffic controllers, controlling the switches and signals that cause some trains to stop so others can cross ahead of them.
At DeKalb, this happens in the DeKalb signal tower – a room that, despite its lofty name, is buried behind a locked, nondescript door on the station’s mezzanine floor.
“This is essentially the beating heart of the B Division – the letters with letters,” said Chris Pangilinan, Chief of Operations and Planning for New York City Transit. “Almost all lines of letters are influenced in some way, directly or indirectly, by all the lines that run through them.”
In the center of the room is the ‘model board’, a large black metal triptych with white lines representing tracks, switches and stations under the tower’s control. Small LED segments light up to indicate when a train has occupied a specific track section.
On top of the model board, amid memos from headquarters, was a small wooden ship and a sign that said “be grateful.”
The tower operators sitting at the board pressed buttons along the rail lines, setting routes through the interlock for oncoming subways as the radio chatter of their crews crackled.
One door away, in a large relay room, rows and rows of 1930s-era electromechanical relays clicked and clacked as tower operators plotted routes and trains moved along the tracks below.
“This is a big tower,” said Shanna Parker, general superintendent for NYC Transit. “It has the B, the D, the Q, N [and] R regularly, the W at certain times – W’s come here in the morning and evening – and the Franklin Ave. Shuttle.’
“You have DeKalb interlock, you have Gold Street interlock, Pacific Street interlock, and you have Prospect Park interlock, all in this tower,” she added.
As she spoke, the lights on the sign began to move, shadowing a train traveling from DeKalb to Atlantic Avenue.
But the lights don’t track the train as much as they identify occupied track blocks, explains Sandy Castillo, an Assistant Chief Signals Officer for the subway system.
“The position is not accurate,” he said. “As you can see here, between DeKalb and Atlantic – which is about half a mile – you only have a certain number of indications. The blocks we detect, it’s a large area.”
That system, known as “block signaling,” only tells tower operators approximately where a train is. This can lead to traffic jams entering the lock.
“They are very large physical blocks – the trains have to be very far apart,” Castillo said. “And that extends the time until you can replace a train in the station.”
In contrast, modern automated signaling – known as communications-based train control or CBTC – involves wireless transponders on a train that communicate with trackside transponders, allowing accurate triangulation of a train’s location.
“With CBTC we can bring a train much closer,” said Castillo. ‘We know exactly where that train is. The timing has improved.”
CBTC – which will require both new rail cars and new signaling equipment – is already in use along the 7 and L trains, part of the E train on the Queens Boulevard Line, and recently went into service on the Culver Line from the F train between West 8th St. and Ditmas Ave. in Brooklyn.
Preliminary work for the CBTC has also been completed along the north end of the A train, as well as the G train’s Crosstown line.
The MTA planned to install CBTC equipment along one of the two lines feeding the DeKalb Interlocking – the Sixth Avenue line of the B, D, F and M trains – in the 2020-2024 capital budget , but had not been able to finance the project. amid delays in the state’s toll collection program.
With the tolls expected to go into effect in 2025, Torres-Springer said signal upgrades are back on schedule for Sixth Avenue. Upgrades to the Broadway line – the N, Q, R and W – are expected to be funded in the upcoming 2025-2029 capital budget.
In total, the MTA is requesting $5.4 billion to upgrade the signals over the next five years, a budget that also includes the CBTC installation on the J and Z in Manhattan and the A and Rockaway Shuttle in southeast Queens includes.
Not only would new signals speed trains through the DeKalb Interlocking, it would also eliminate the need for the tower, allowing the interlocking to be controlled from afar from the MTA’s Rail Control Center in Midtown Manhattan.
But there is no firm timeline yet on when DeKalb can be fully converted — with new equipment, signals and trains — to a modern CBTC system.
For now, passengers waiting to go through the lock will have to sit tight and hope the train is held on the bridge, where they can still enjoy the view.
