Details
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LocationBronx, Brooklyn, Manhattan, Queens
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TypeInfrastructure, Signals
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StatusConstruction
Area Map
Timeline
- 2015-2017: Contracts awarded for CBTC on the Queens Boulevard Line
- 2020: CBTC construction work begins on the Culver and 8 Av lines
- 2023: CBTC construction work begins on the Crosstown Line
- 2009: CBTC is installed on the L line
- 2019: CBTC is installed on the 7 line
About the project
You may think of signals as the devices that look like traffic lights on our tracks. But they're part of a complex system with multiple components that helps keep our trains moving safely.
The subway's signal system is like its nervous system. It provides instructions to trains so they know when they can and can't move, how fast they should move, and where track switches are set to route trains. The system is designed to keep trains spaced at safe distances and ensure they can't move in ways that could put anyone in danger.
Our legacy signal system relies on technology that dates back to the opening of the subway 120 years ago. We've made improvements to modernize our signals over the decades, but the basic technology is unchanged. Newer, modern signals can provide our riders with faster, more frequent, smoother, and more reliable service.
To make this a reality, we're replacing our existing signals with the international gold standard of signal systems. Known as communications-based train control (or CBTC), this system uses wireless connectivity to keep trains in constant contact with a centralized system that controls their movement.
Where we're installing CBTC
The Culver Line, on the
CBTC is coming to the in Brooklyn between Church Av and West 8 St in Coney Island.
Learn more about CBTC on the Culver Line.
The Crosstown Line, on the
We're installing CBTC on the between Court Sq in Queens and Church Av in Brooklyn.
The lines on 8 Av
We're installing CBTC between 59 St in Manhattan and High St in Brooklyn.
Learn more about CBTC on 8 Av.
The Queens Blvd Line, on the
We're in the final stages of rolling out CBTC along Queens Blvd and are in the process of implementing it between Kew Gardens-Union Tpke and Jamaica-179 St.
Service changes related to CBTC installation may affect your trip on these lines. View our Planned Service Changes page for the most up-to-date planned service change information. Use the MTA app or visit our homepage to plan your trip. Look for posted signs in stations, and sign up for email and text alerts or subscribe to our MTA Weekender newsletter.
How CBTC works
Right now, in most of our system, we only know where a train is only because of its physical connection with the track. When the train's steel wheels make contact with the steel rails, they complete an electrical circuit that tells the signaling system a section of track is occupied. The system then prevents the following train from entering the occupied section of track.
With CBTC, we have equipment on both trains and along the tracks, or "wayside." Trains communicate with wayside equipment that connects back via a private network to servers at our Operations Control Center.
CBTC is a complex system that combines hardware, software, and the communication links between them to deliver better train service.
Today's signals: Fixed-block signaling
With our legacy signal system, all we know is that some part of a train is in some part of a section of track. These sections, known as fixed blocks, can be over 1,000 feet long.
This has some drawbacks: We don't know the exact position or speed of a train, so we have to run them farther apart to create a safety buffer.
Our current system also relies on a lot of infrastructure that's expensive to install and maintain. In some cases, we're one of the only transit agencies still using the components in our signal system. This means we either need to pay a lot of money to acquire replacements or fabricate them ourselves.
Plus, the circuitry and electro-mechanical relays that underpin our signal block system are delicate and require more maintenance.
CBTC: Moving-block signaling
With CBTC, equipment on trains and tracks tells us exactly where a train is, rather than just that there's a train somewhere on a pre-defined section of track.
This lets us keep trains a safe distance apart based on their exact locations. The section of track around each train that needs to be kept clear moves with the train, rather than being based on fixed blocks. This is why CBTC is known as a moving-block system.
This lets us run trains more closely together. If trains run more closely, they can run more frequently. And if trains run more frequently, our system can move more people on less crowded trains.
What is CBTC?
What it takes to build a CBTC system
We're converting existing lines to CBTC, which is more complicated than building a new train line with CBTC from scratch. Before we can build the system, we need to fully plan and design all of its components.
This can be a years-long effort that involves:
- Surveying an entire line to understand its existing assets and converting that into a database
- Determining locations for wayside CBTC equipment
- Retrofitting our existing trains with on-board CBTC equipment that connects them to the larger system and provides them with operating instructions
- Installing wayside equipment on and near tracks and connecting it back to the centralized CBTC system
- Customizing the software used to run trains to determine operating rules and service specifications (How often do trains run? How fast do they go?)
- Creating a plan to transition from the traditional signal system to CBTC
- Testing the new system exhaustively under various scenarios to find failure points and make adjustments so service runs safely and efficiently
How CBTC improves your ride
Faster, more frequent service. Running trains closer together means we can run more frequent trains, leading to shorter waits and less crowding. Trains can also travel at higher speeds without compromising safety.
More reliable service. The and , the first lines converted to use CBTC, are our best-performing lines. On-time performance on these lines is consistently near or above 90%. And signal problems are among the leading causes of delays in subway service. Upgrading our technology means fewer issues and a faster recovery when issues do happen.
A smoother ride. The computerized automatic train operation (ATO) system that's part of CBTC means there are fewer variations between how train operators run trains. Acceleration and braking is controlled by the system, so customers can expect more consistency and improved performance.
More accurate arrival information. CBTC gives us much more precise information about where a train is. This improves the accuracy of the real-time arrival information you see in stations and apps.