# Communications-based train control

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Railway signaling system

"CBTC" redirects here. For other uses, see [CBTC (disambiguation)](/source/CBTC_(disambiguation)).

CBTC deployment in [Madrid Metro](/source/Madrid_Metro), Spain

Santo Amaro station on [Line 5](/source/Line_5_(S%C3%A3o_Paulo_Metro)) of the partially CBTC-enabled [São Paulo Metro](/source/S%C3%A3o_Paulo_Metro)

Automated track-bound traffic Automatic train operation Automated guideway transit Automated people mover Personal rapid transit CBTC ETCS History of train automation Automated transit networks suppliers Lists of automated train systems Defunct systems GoA2 GoA3+ Related topics Self-driving car Unmanned surface vehicle v t e

**Communications-based train control** (**CBTC**) is a [railway signaling](/source/Railway_signaling) system that uses [telecommunications](/source/Telecommunications) between the [train](/source/Train) and track equipment for traffic management and infrastructure control. CBTC allows a train's position to be known more accurately than with traditional signaling systems. This can make railway traffic management safer and more efficient. [Rapid transit](/source/Rapid_transit) systems (and other railway systems) are able to reduce [headways](/source/Headway) while maintaining or even improving safety.

A CBTC system is a "continuous, [automatic train control](/source/Automatic_train_control) system utilizing high-resolution train location determination, independent from [track circuits](/source/Track_circuits); continuous, high-capacity, bidirectional train-to-wayside data communications; and trainborne and wayside [processors](/source/Processor_(computing)) capable of implementing [automatic train protection](/source/Automatic_train_protection) (ATP) functions, as well as optional [automatic train operation](/source/Automatic_train_operation) (ATO) and **automatic train supervision** (**ATS**) functions," as defined in the [IEEE](/source/IEEE) 1474 standard.[1]

## Background and origin

CBTC is a signalling standard defined by the [IEEE](/source/IEEE) 1474 standard.[1] The original version was introduced in 1999 and updated in 2004.[1] The aim was to create consistency and standardisation between digital railway signalling systems that allow for an increase in train capacity through what the standard defines as high-resolution train location determination.[1] The standard therefore does not require the use of [moving block](/source/Moving_block) railway signalling, but in practice this is the most common arrangement.[2][3][4][5][6][7]

### Moving block

Main article: [Moving block](/source/Moving_block)

Traditional signalling systems detect trains in discrete sections of the track called '[blocks](/source/Block_signal)', each protected by signals that prevent a train entering an occupied block. Since every block is a fixed section of track, these systems are referred to as [fixed block](/source/Fixed_block) systems.[8]

In a moving block CBTC system the protected section for each train is a "block" that moves with and trails behind it, and provides continuous communication of the train's exact position via radio, inductive loop, etc.[9]

The SFO [AirTrain](/source/AirTrain_(SFO)) in [San Francisco Airport](/source/San_Francisco_Airport) was the first radio-based CBTC system.

As a result, [Bombardier](/source/Bombardier_Transportation) opened the world's first radio-based CBTC system at [San Francisco airport](/source/San_Francisco_airport)'s [automated people mover](/source/Automated_people_mover) (APM) in February 2003.[10] A few months later, in June 2003, [Alstom](/source/Alstom) introduced the railway application of its radio technology on the [Singapore North East Line](/source/North_East_Line). CBTC has its origins in the [loop-based](/source/Inductive_loop) systems developed by [Alcatel SEL](/source/Alcatel-Lucent) (later [Thales](/source/Thales_Group), now [Hitachi Rail](/source/Hitachi_Rail)) for the [Bombardier Automated Rapid Transit](/source/Bombardier_Advanced_Rapid_Transit) (ART) systems in [Canada](/source/Canada) during the mid-1980s.

These systems, which were also referred to as [transmission-based train control](/source/Transmission-based_train_control) (TBTC), made use of [inductive loop](/source/Inductive_loop) transmission techniques for track to train communication, introducing an alternative to [track circuit](/source/Track_circuit) based communication. This technology, operating in the 30–60 [kHz](/source/KHz) [frequency](/source/Frequency) range to communicate trains and wayside equipment, was widely adopted by the [metro](/source/Rapid_transit) operators in spite of some [electromagnetic compatibility](/source/Electromagnetic_compatibility) (EMC) issues, as well as other installation and maintenance concerns (see [SelTrac](/source/SelTrac) for further information regarding transmission-based train-control).

As with new application of any technology, some problems arose at the beginning, mainly due to compatibility and interoperability aspects.[11][12] However, there have been relevant improvements since then, and currently the reliability of the radio-based communication systems has grown significantly.

Moreover, it is important to highlight that not all the systems using [radio communication](/source/Radio_communication) technology are considered to be CBTC systems. So, for clarity and to keep in line with the [state-of-the-art](/source/State-of-the-art) solutions for operator's requirements,[12] this article only covers the latest [moving block](/source/Moving_block) principle based (either true [moving block](/source/Moving_block) or [virtual block](https://en.wikipedia.org/w/index.php?title=Virtual_block&action=edit&redlink=1), so not dependent on track-based detection of the trains)[1] CBTC solutions that make use of the [radio communications](/source/Radio_communications).

## Main features

### CBTC and moving block

CBTC systems are modern railway signaling systems that can mainly be used in urban railway lines (either [light](/source/Light_rail) or [heavy](/source/Rapid_transit)) and [APMs](/source/Automated_people_mover), although it could also be deployed on [commuter lines](/source/Commuter_rail). For [main lines](/source/Main_line_(railway)), a similar system might be the [European Railway Traffic Management System](/source/European_Railway_Traffic_Management_System) ERTMS Level 3 (not yet fully defined [*[when?](https://en.wikipedia.org/wiki/Wikipedia:Manual_of_Style/Dates_and_numbers#Chronological_items)*]). In the modern CBTC systems the trains continuously calculate and communicate their status via radio to the wayside equipment distributed along the line. This status includes, among other parameters, the exact position, speed, travel direction and [braking distance](/source/Braking_distance).

This information allows calculation of the area potentially occupied by the train on the track. It also enables the wayside equipment to define the points on the line that must never be passed by the other trains on the same track. These points are communicated to make the trains automatically and continuously adjust their speed while maintaining the [safety](/source/Safety_engineering) and comfort ([jerk](/source/Jerk_(physics))) requirements. So, the trains continuously receive information regarding the distance to the preceding train and are then able to adjust their [safety distance](https://en.wikipedia.org/w/index.php?title=Safety_distance&action=edit&redlink=1) accordingly.

The safety distance (safe-braking distance) between trains in fixed block and moving block signalling systems

From the [signalling system](/source/Railway_signal) perspective, the first figure shows the total occupancy of the leading train by including the whole [blocks](/source/Block_signal) which the train is located on. This is due to the fact that it is impossible for the system to know exactly where the train actually is within these [blocks](/source/Block_signal). Therefore, the [fixed block](/source/Fixed_block) system only allows the following train to move up to the last unoccupied [block](/source/Block_signal)'s border.

In a [moving block](/source/Moving_block) system as shown in the second figure, the train position and its [braking curve](https://en.wikipedia.org/w/index.php?title=Braking_curve&action=edit&redlink=1) is continuously calculated by the trains, and then communicated via radio to the wayside equipment. Thus, the wayside equipment is able to establish protected areas, each one called Limit of Movement Authority (LMA), up to the nearest obstacle (in the figure the tail of the train in front). Movement Authority (MA) is the permission for a train to move to a specific location within the constraints of the infrastructure and with supervision of speed.[13]

End of Authority is the location to which the train is permitted to proceed and where target speed is equal to zero. End of Movement is the location to which the train is permitted to proceed according to an MA. When transmitting an MA, it is the end of the last section given in the MA.[13]

It is important to mention that the occupancy calculated in these systems must include a safety margin for location uncertainty (in yellow in the figure) added to the length of the train. Both of them form what is usually called 'Footprint'. This safety margin depends on the accuracy of the [odometry](/source/Odometry) system in the train.

CBTC systems based on moving block allows the reduction of the [safety distance](https://en.wikipedia.org/w/index.php?title=Safety_distance&action=edit&redlink=1) between two consecutive trains. This distance is varying according to the continuous updates of the train location and speed, maintaining the [safety](/source/Safety_engineering) requirements. This results in a reduced [headway](/source/Headway) between consecutive trains and an increased transport [capacity](/source/Headway#Capacity).

### Grades of automation

Modern CBTC systems allow different levels of automation or [grades of automation](/source/Automatic_train_operation) (GoA), as defined and classified in the [IEC](/source/IEC) 62290–1.[14] In fact, CBTC is not a synonym for "[driverless](/source/Automatic_train_operation)" or "automated trains" although it is considered as a basic enabler technology for this purpose.

There are four grades of automation available:

- GoA 0 – On-sight, with no automation

- GoA 1 – Manual, with a driver controlling all train operations.

- GoA 2 – Semi-automatic Operation (STO), starting and stopping are automated, but a driver who sits in the cab operates the doors and drives in emergencies

- GoA 3 – Driverless Train Operation (DTO), starting and stopping are automated, but a crew member operates the doors from within the train

- GoA 4 – Unattended Train Operation (UTO), starting, stopping and doors are all automated, with no required crew member on board

### Main applications

CBTC systems allow optimal use of the railway infrastructure as well as achieving maximum [capacity](/source/Headway#Capacity) and minimum [headway](/source/Headway) between operating trains, while maintaining the [safety](/source/Safety_engineering) requirements. These systems are suitable for the new highly demanding urban lines, but also to be overlaid on existing lines in order to improve their performance.[5]

Of course, in the case of upgrading existing lines the design, installation, test and commissioning stages are much more critical. This is mainly due to the challenge of deploying the overlying system without disrupting the [revenue](/source/Revenue) service.[15]

### Main benefits

The evolution of the technology and the experience gained in operation over the last 30 years means that modern CBTC systems are more reliable and less prone to failure than older train control systems. CBTC systems normally have less wayside equipment and their diagnostic and monitoring tools have been improved, which makes them easier to implement and, more importantly, easier to maintain.[16]

CBTC technology is evolving, making use of the latest techniques and components to offer more compact systems and simpler architectures. For instance, with the advent of modern electronics it has been possible to build in redundancy so that single failures do not adversely impact operational availability.

Moreover, these systems offer complete flexibility in terms of operational schedules or timetables, enabling urban rail operators to respond to the specific traffic demand more swiftly and efficiently and to solve traffic congestion problems. In fact, automatic operation systems have the potential to significantly reduce the [headway](/source/Headway) and improve the [traffic capacity](/source/Headway#Capacity) compared to manual driving systems.[17][18]

Finally, it is important to mention that the CBTC systems have proven to be more energy efficient than traditional manually driven systems.[16] The use of new functionalities, such as automatic driving strategies or a better adaptation of the transport offer to the actual demand, allows significant energy savings reducing the power consumption.

### Risks

The primary risk of an electronic train control system is that if the communications link between any of the trains is disrupted, all or part of the system might have to enter a [failsafe](/source/Failsafe) state until the problem is remedied. Depending on the severity of the communication loss, this state can range from vehicles temporarily reducing speed, coming to a halt or operating in a degraded mode until communications are re-established. If communication outage is permanent, some sort of [contingency operation](/source/Contingency_plan) must be implemented which may consist of manual operation using [absolute block](/source/Absolute_block) or, in the worst case, the [substitution of an alternative form of transportation](/source/Bustitution).[19]

As a result, high availability of CBTC systems is crucial for proper operation, especially if such systems are used to increase transport capacity and reduce headway. System redundancy and recovery mechanisms must then be thoroughly checked to achieve a high robustness in operation. With the increased availability of the CBTC system, there is also a need for extensive training and periodical refresh of system operators on the [recovery procedures](/source/Recovery_procedure). In fact, one of the major system hazards in CBTC systems is the probability of human error and improper application of recovery procedures if the system becomes unavailable.

Communications failures can result from equipment malfunction, [electromagnetic interference](/source/Electromagnetic_interference), weak signal strength or saturation of the communications medium.[20] In this case, an interruption can result in a service brake or [emergency brake](/source/Emergency_brake_(train)) application as real time situational awareness is a critical safety requirement for CBTC and if these interruptions are frequent enough it could seriously impact service. This is the reason why, historically, CBTC systems first implemented radio communication systems in 2003, when the required technology was mature enough for critical applications.

In systems with poor [line of sight](/source/Line_of_sight) or spectrum/bandwidth limitations a larger than anticipated number of transponders may be required to enhance the service. This is usually more of an issue with applying CBTC to existing transit systems in tunnels that were not designed from the outset to support it. An alternate method to improve system availability in tunnels is the use of leaky feeder cable that, while having higher initial costs (material + installation) achieves a more reliable radio link.

With the emerging services over open ISM radio bands (i.e. 2.4 GHz and 5.8 GHz) and the potential disruption over critical CBTC services, there is an increasing pressure in the international community (ref. report 676 of UITP organization, Reservation of a Frequency Spectrum for Critical Safety Applications dedicated to Urban Rail Systems) to reserve a frequency band specifically for radio-based urban rail systems. Such decision would help standardize CBTC systems across the market (a growing demand from most operators) and ensure availability for those critical systems.

As a CBTC system is required to have [high availability](/source/High_availability) and particularly, allow for a graceful degradation, a secondary method of signaling might be provided to ensure some level of non-degraded service upon partial or complete CBTC unavailability.[21] This is particularly relevant for brownfield implementations (lines with an already existing signalling system) where the infrastructure design cannot be controlled and coexistence with legacy systems is required, at least, temporarily.[22]

For example, the [BMT Canarsie Line](/source/BMT_Canarsie_Line) in New York City was outfitted with a backup [automatic block signaling](/source/Automatic_block_signaling) system capable of supporting 12 trains per hour (tph), compared with the 26 tph of the CBTC system. Although this is a rather common architecture for resignalling projects, it can negate some of the cost savings of CBTC if applied to new lines. This is still a key point in the CBTC development (and is still being discussed), since some providers and operators argue that a fully redundant architecture of the CBTC system may however achieve high availability values by itself.[22]

In principle, CBTC systems may be designed with centralized supervision systems in order to improve maintainability and reduce installation costs. If so, there is an increased risk of a single point of failure that could disrupt service over an entire system or line. Fixed block systems usually work with distributed logic that are normally more resistant to such outages. Therefore, a careful analysis of the benefits and risks of a given CBTC architecture (centralized vs. distributed) must be done during system design.

When CBTC is applied to systems that previously ran under complete human control with operators working on sight it may actually result in a reduction in capacity (albeit with an increase in safety). This is because CBTC operates with less positional certainty than human sight and also with greater [margins for error](/source/Margin_of_error) as worst-case train parameters are applied for the design (e.g. guaranteed emergency brake rate vs. nominal brake rate). For instance, CBTC introduction in Philly's [Center City trolley tunnel](/source/SEPTA_Subway%E2%80%93Surface_Trolley_Lines) resulted initially in a marked increase in travel time and corresponding decrease in capacity when compared with the unprotected manual driving. This was the offset to finally eradicate vehicle collisions which on-sight driving cannot avoid and showcases the usual conflicts between operation and safety.

## Architecture

The architecture of a CBTC system

An Alstom Eurobalise on Montreal's [Réseau express métropolitain](/source/R%C3%A9seau_express_m%C3%A9tropolitain)

The typical architecture of a modern CBTC system comprises the following main subsystems:

1. **Wayside equipment**, which includes [balises](/source/Balise), [interlockings](/source/Interlocking) and the subsystems controlling every zone in the line or network (typically containing the wayside [ATP](/source/Automatic_Train_Protection) and [ATO](/source/Automatic_train_operation) functionalities). Depending on the suppliers, the architectures may be centralized or distributed. The control of the system is performed from a central command [automatic train supervision](/source/Automatic_train_supervision) (ATS) system, though local control subsystems may be also included as a fallback.

1. **CBTC onboard equipment**, including [ATP](/source/Automatic_Train_Protection) and [ATO](/source/Automatic_train_operation) subsystems in the vehicles.

1. **Train to wayside communication subsystem**, currently based on [radio links](/source/Radio_communication).

Thus, although a CBTC architecture is always depending on the supplier and its technical approach, the following logical components may be found generally in a typical CBTC architecture:

- **Onboard ATP system**. This subsystem is in charge of the continuous control of the train speed according to the safety profile, and applying the brake if it is necessary. It is also in charge of the communication with the wayside ATP subsystem in order to exchange the information needed for a safe operation (sending speed and braking distance, and receiving the limit of movement authority for a safe operation).

- **Onboard ATO system**. It is responsible for the automatic control of the traction and braking effort in order to keep the train under the threshold established by the ATP subsystem. Its main task is either to facilitate the driver or attendant functions, or even to operate the train in a fully automatic mode while maintaining the traffic regulation targets and passenger comfort. It also allows the selection of different automatic driving strategies to adapt the runtime or even reduce the power consumption.

- **Wayside ATP system**. This subsystem undertakes the management of all the communications with the trains in its area. Additionally, it calculates the limits of movement authority that every train must respect while operating in the mentioned area. This task is therefore critical for the operation safety.

- **Wayside ATO system**. It is in charge of controlling the destination and regulation targets of every train. The wayside ATO functionality provides all the trains in the system with their destination as well as with other data such as the [dwell time](/source/Terminal_dwell_time) in the stations. Additionally, it may also perform auxiliary and non-safety related tasks, for instance alarm/event communication and management, or handling skip/hold station commands.

- **Communication system**. The CBTC systems integrate a [digital networked radio](/source/Digital_radio) system by means of [antennas](/source/Antennas) or [leaky feeder](/source/Leaky_feeder) cable for the bi-directional communication between the track equipment and the trains. The 2,4[GHz](/source/GHz) [band](/source/Radio_frequency) is commonly used in these systems (same as [WiFi](/source/WiFi)), though other alternative [frequencies](/source/Radio_frequency) such as 900 MHz ([US](/source/US)), 5.8 GHz or other licensed bands may be used as well.

- **ATS system**. The ATS system is commonly integrated within most of the CBTC solutions. Its main task is to act as the interface between the operator and the system, managing the traffic according to the specific regulation criteria. Other tasks may include the event and alarm management as well as acting as the interface with external systems.

- **[Interlocking](/source/Interlocking) system**. When needed as an independent subsystem (for instance as a fallback system), it will be in charge of the vital control of the trackside objects such as [switches](/source/Railway_switch) or [signals](/source/Railway_signal), as well as other related functionality. In the case of simpler networks or lines, the functionality of the interlocking may be integrated into the wayside ATP system.

## Projects

CBTC technology has been (and is being) successfully implemented for a variety of applications as shown in the figure below (mid 2011). They range from some implementations with short track, limited numbers of vehicles and few operating modes (such as the airport [APMs](/source/Automated_people_mover) in Heathrow or Gatwick), to complex overlays on existing railway networks carrying more than a million passengers each day and with more than 100 trains (such as [London Underground](/source/London_Underground) [Jubilee Line](/source/Jubilee_Line) and [Northern Line](/source/Northern_Line), [MTR](/source/MTR) [Tuen Ma Line](/source/Tuen_Ma_Line), [Klang Valley Mass Rapid Transit](/source/Klang_Valley_Mass_Rapid_Transit), [Kajang Line](/source/Kajang_Line), and [Putrajaya Line](/source/Putrajaya_Line)).[4]

Despite the difficulty, the table below tries to summarize and reference the main radio-based CBTC systems deployed around the world as well as those ongoing projects being developed. Besides, the table distinguishes between the implementations performed over existing and operative systems ([brownfield](/source/Brownfield_land)) and those undertaken on completely new lines ([greenfield](/source/Greenfield_project)).

### List

This is a [dynamic list](https://en.wikipedia.org/wiki/Wikipedia:WikiProject_Lists#Dynamic_lists) and may never be able to satisfy particular standards for completeness. You can help by [editing the page](https://en.wikipedia.org/wiki/Special:EditPage/Communications-based_train_control) to add missing items, with references to [reliable sources](https://en.wikipedia.org/wiki/Wikipedia:Reliable_sources).

This list is sortable, and is initially sorted by year. Click on the icon on the right side of the column header to change sort key and sort order.

Location/system Lines Supplier Solution Commissioning km No. of trains Type of field Grade of automation Notes Toronto Subway Line 3 (SRT) Thales SelTrac 1985 6.4 7 Greenfield UTO With train attendants who monitor door status, and drive trains in the event of a disruption. Réseau express métropolitain (Montréal) A1-4 Alstom Urbalis 400[23] 2023-2027 67 212 Greenfield UTO Initially opened in 2023, The full 67 km is projected to be opened in 2027 SkyTrain (Vancouver) Expo Line, Millennium Line, Canada Line Thales SelTrac 1985 85.4 176 Greenfield UTO Detroit Detroit People Mover Thales SelTrac 1987 4.7 12 Greenfield UTO London Docklands Light Railway Thales SelTrac 1987 38 149 Greenfield DTO With train attendants (T\train captains) who drive trains in the event of a disruption. San Francisco Airport AirTrain Bombardier CITYFLO 650 2003 5 38 Greenfield UTO Seattle-Tacoma Airport Satellite Transit System Bombardier CITYFLO 650 2003 3 22 Brownfield UTO Singapore MRT North East Line Alstom Urbalis 300 2003 20 43 Greenfield UTO With train attendants (train captains) who drive trains in the event of a disruption. Hong Kong MTR Tuen Ma line Thales SelTrac 2020 (Tuen Ma Line Phase 1) 2021 (Tuen Ma Line and former West Rail Line) 57 65 Greenfield (Tai Wai to Hung Hom section only) Brownfield (other sections) STO Existing sections were upgraded from SelTrac IS Disneyland Resort line 2005 3 3 Greenfield UTO Las Vegas Monorail Thales SelTrac 2004 6 36 Greenfield UTO Dallas–Fort Worth Airport Skylink Bombardier CITYFLO 650 2005 10 64 Greenfield UTO Lausanne Metro Line M2 Alstom Urbalis 300 2008 6 18 Greenfield UTO London Heathrow Airport Heathrow APM Bombardier CITYFLO 650 2008 1 9 Greenfield UTO Madrid Metro , Bombardier CITYFLO 650 2008 48 143 Brownfield STO McCarran Airport McCarran Airport APM Bombardier CITYFLO 650 2008 2 10 Brownfield UTO Bangkok BTS Skytrain Silom Line, Sukhumvit Line Bombardier CITYFLO 450[24] 2009 (Mo Chit - On Nut & National Stadium - Wongwian Yai sections) 2011 (On Nut extension) 2015 (Samrong extension) 2018 (Kheha extension) 2019 (Khu Khot extension) 64.26 98 Brownfield (Mo Chit to On Nut and National Stadium to Saphan Taksin sections) Greenfield (other sections) STO Upgraded from Siemens Trainguard LZB700M CTC in 2009. Gold Line CITYFLO 650 2020 1.7 3 Greenfield UTO Bangkok MRT Purple Line Bombardier CITYFLO 650 2015 23 21 Greenfield STO With train attendants who drive trains in the event of a disruption. These train attendants are on standby in the train. Pink, Yellow 2021 62.52 58 UTO Barcelona Metro , , Siemens Trainguard MT CBTC 2009 (Line 9, Line 11) 2010 (Line 10) 46 50 Greenfield UTO New York City Subway BMT Canarsie Line, IRT Flushing Line Siemens Trainguard MT CBTC 2009 17 69[note 1] Brownfield STO Singapore MRT Circle Line Alstom Urbalis 300 2009 35 64 Greenfield UTO With train attendants (Rovers) who drive trains in the event of a disruption. These train attendants are also on standby between Botanic Gardens and Caldecott stations. Taipei Metro Neihu-Mucha Bombardier CITYFLO 650 2009 26 76 Greenfield and Brownfield UTO Washington-Dulles Airport Dulles APM Thales SelTrac 2009 8 29 Greenfield UTO São Paulo Metro 1, 2, 3 Alstom Urbalis 2010 62 142 Greenfield and Brownfield UTO CBTC operates in Lines 1 and 2 and it is being installed in Line 3 4 Siemens Trainguard MT CBTC 13 29 Greenfield First UTO line in Latin America London Underground Jubilee line Thales SelTrac 2010 37 63 Brownfield STO London Gatwick Airport Shuttle Transit APM Bombardier CITYFLO 650 2010 1 6 Brownfield UTO Milan Metro 1 Alstom Urbalis 2010 27 68 Brownfield STO Philadelphia SEPTA SEPTA subway–surface trolley lines Bombardier CITYFLO 650 2010 8 115 STO B&G Metro Busan-Gimhae Light Rail Transit Thales SelTrac 2011 23.5 25 Greenfield UTO Dubai Metro Red, Green Thales SelTrac 2011 70 85 Greenfield UTO Madrid Metro Extension MetroEste Invensys Sirius 2011 9 ? Brownfield STO Paris Métro 1 Siemens Trainguard MT CBTC 2011 16 53 Brownfield DTO Sacramento International Airport Sacramento APM Bombardier CITYFLO 650 2011 1 2 Greenfield UTO Yongin EverLine Bombardier CITYFLO 650 2011 19 30 UTO Algiers Metro 1 Siemens Trainguard MT CBTC 2012 9 14 Greenfield STO Istanbul Metro M4 Thales SelTrac 2012 21.7 Greenfield M5 Bombardier CityFLO 650 2017-2018 16.9 21 Greenfield UTO Opened in 2 phases the first in 2017 and the second in 2018 Ankara Metro M1 Ansaldo STS CBTC 2018 14.6 Brownfield STO M2 Ansaldo STS CBTC 2014 16.5 Greenfield STO M3 Ansaldo STS CBTC 2014 15.5 Greenfield STO M4 Ansaldo STS CBTC 2017 9.2 Greenfield STO Mexico City Metro Alstom Urbalis 2012 25 30 Greenfield STO Siemens Trainguard MT CBTC 2022-2024 18 39 Brownfield DTO New York City Subway IND Culver Line Thales & Siemens Various 2012 Greenfield A test track was retrofitted in 2012; the line's other tracks will be retrofitted by the early 2020s. Phoenix Sky Harbor Airport PHX Sky Train Bombardier CITYFLO 650 2012 3 18 Greenfield UTO Riyadh KAFD Monorail Bombardier CITYFLO 650 2012 4 12 Greenfield UTO São Paulo Commuter Lines 8, 10, 11 Invensys Sirius 2012 107 136 Brownfield UTO Caracas Metro 1 Invensys Sirius 2013 21 48 Brownfield Málaga Metro , Alstom Urbalis 2013 17 15 Greenfield ATO Paris Métro 3, 5 Ansaldo STS / Siemens Inside RATP's Ouragan project 2010, 2013 26 40 Brownfield STO 13 Thales SelTrac 23 66 Toronto subway 1 Alstom Urbalis 400 2017 to 2022 76.78[6] 65[6] Brownfield (Finch to Sheppard West) Greenfield (Sheppard West to Vaughan) STO CBTC active between Vaughan Metropolitan Centre and Eglinton stations as of October 2021.[25] The entire line is scheduled to be fully upgraded by 2022.[26][7] Singapore MRT Downtown Line Invensys Sirius 2013 42 92 Greenfield UTO With train attendants who drive trains in the event of a disruption. Budapest Metro M2, M4 Siemens Trainguard MT CBTC 2013 (M2) 2014 (M4) 17 41 Line M2: STO Line M4: UTO Dubai Metro Al Sufouh LRT Alstom Urbalis 2014 10 11 Greenfield STO Edmonton LRT Capital Line, Metro Line Thales SelTrac 2014 24 double track 94 Brownfield DTO Helsinki Metro 1 Siemens Trainguard MT CBTC 2014 35 45.5 Greenfield and Brownfield STO[27] Hong Kong International Airport Hong Kong International Airport Automated People Mover Thales SelTrac 2014 4 14 Brownfield UTO Incheon Subway 2 Thales SelTrac 2014 29 37 Greenfield UTO Jeddah Airport King Abdulaziz APM Bombardier CITYFLO 650 2014 2 6 Greenfield UTO London Underground Northern line Thales SelTrac 2014 58 106 Brownfield STO Salvador Metro 4 Thales[3] SelTrac 2014 33 29 Greenfield DTO Massachusetts Bay Transportation Authority Mattapan Line Argenia SafeNet CBTC 2014 6 12 Greenfield STO Munich Airport Munich Airport T2 APM Bombardier CITYFLO 650 2014 1 12 Greenfield UTO Shinbundang Line Dx Line Thales SelTrac 2014 30.5 12 Greenfield UTO Panama Metro 1 Alstom Urbalis 2014 13.7 17 Greenfield ATO São Paulo Metro 15 Bombardier CITYFLO 650 2014 14 27 Greenfield UTO Amsterdam Metro 50, 51, 52, 53, 54 Alstom Urbalis 2015 62 85 Greenfield and Brownfield STO Delhi Metro Line 7, Line 9 Bombardier CITYFLO 650 2018 (Temp. Driver on Board) 2021 (Full ATO Operations) 2024 (transitioning to UTO) 55 São Paulo Metro 5 Bombardier CITYFLO 650 2015 20 34 Brownfield & Greenfield UTO Buenos Aires Underground Siemens Trainguard MT CBTC 2016 8 20 ? ? 4.5 18 Hong Kong MTR South Island line Alstom Urbalis 400 2016 7 10 Greenfield UTO Hyderabad Metro L1, L2, L3 Thales SelTrac 2016 72 57 Greenfield STO Kochi Metro L1 Alstom Urbalis 400 2016 26 25 Greenfield ATO New York City Subway IRT Flushing Line Thales SelTrac 2016 17 46[note 2] Brownfield and Greenfield STO IND Queens Boulevard Line Siemens/Thales Trainguard MT CBTC 2017–2022 [note 3] 21.9 [note 4] 309[note 5] Brownfield ATO Train conductors will be located aboard the train because other parts of the routes using the Queens Boulevard Line will not be equipped with CBTC. Kuala Lumpur Metro (LRT) Line 5, Kelana Jaya Line Thales SelTrac 2016 91.5 126 Brownfield UTO Metro Santiago Alstom Urbalis 2016 20 42 Greenfield and Brownfield DTO Walt Disney World Walt Disney World Monorail System Thales SelTrac 2016 22 15 Brownfield UTO Delhi Metro Line-8 Nippon Signal SPARCS 2017 (Temp. Driver on Board) 2021 (Full ATO Operations) Greenfield UTO Lille Metro 1 Alstom Urbalis 2017 15 27 Brownfield UTO Lucknow Metro L1 Alstom Urbalis 2017 23 20 Greenfield ATO Metro Santiago Thales SelTrac 2017 15.4 15 Greenfield UTO Stockholm Metro Red line Ansaldo STS CBTC 2017 41 30 Brownfield STO->UTO Singapore MRT North–South Line Thales SelTrac 2017 45.3 198 Brownfield UTO[28] With train attendants (train captains) who drive trains in the event of a disruption. These train attendants are on standby in the train. East–West Line 2018 57.2 198 Brownfield (original line) Greenfield (Tuas West Extension only) With train attendants who drive trains in the event of a disruption. These train attendants are on standby in the train. Copenhagen S-Train All lines Siemens Trainguard MT CBTC 2021 170 136 Brownfield STO Doha Metro L1 Thales SelTrac 2018 33 35 Greenfield ATO New York City Subway IND Eighth Avenue Line Siemens/Thales Trainguard MT CBTC 2018–2024 [note 6] 9.3 Brownfield ATO Train conductors will be located aboard the train because other parts of the routes using the Eighth Avenue Line will not be equipped with CBTC. O-Train Thales SelTrac 2018 12.5 34 Greenfield STO Port Authority Trans-Hudson (PATH) All lines Siemens Trainguard MT CBTC 2018 22.2 50 Brownfield ATO Rennes ART B Siemens Trainguard MT CBTC 2018 12 19 Greenfield UTO Riyadh Metro L4, L5 and L6 Alstom Urbalis 2018 64 69 Greenfield ATO Sosawonsi Co. (Gyeonggi-do) Seohae Line Siemens Trainguard MT CBTC 2018 23.3 7 Greenfield ATO Buenos Aires Underground TBD TBD 2019 11 26 TBD TBD Gimpo Gimpo Goldline Nippon Signal SPARCS 2019 23.63 23 Greenfield UTO Jakarta MRT North–south line Nippon Signal SPARCS 2019 20.1 16 Greenfield STO Panama Metro 2 Alstom Urbalis 2019 21 21 Greenfield ATO Metro Santiago Thales SelTrac 2019 21.7 22 Greenfield UTO Sydney Metro Metro North West & Bankstown Line Alstom Urbalis 400 2019 37 22 Brownfield UTO Singapore MRT Thomson–East Coast Line Alstom Urbalis 400 2020 43 91 Greenfield UTO Suvarnabhumi Airport APM MNTB to SAT-1 Siemens Trainguard MT CBTC 2020 1 6 Greenfield UTO Bucharest Metro Line M5 Alstom Urbalis 400 2020 6.9 13 STO To be fully operational after the delivery of the 13 Alstom Metropolis BM4 trains. Bay Area Rapid Transit Red Line, Orange Line, Yellow Line, Green Line, Blue Line Hitachi Rail STS CBTC 2030 211.5 Brownfield STO Lahore Orange Line Alstom-Casco Urabliss888 2020 27 27 (CRRC) Greenfield ATO Hong Kong MTR East Rail line Siemens Trainguard MT CBTC 2021 41.5 37 Brownfield STO Lisbon Metro Blue Line, Yellow Line, Green Line[29] Siemens Trainguard MT CBTC 2021-2027 33.7 84 Brownfield STO Baselland Transport (BLT) Line 19 Waldenburgerbahn Stadler NOVA Pro CBTC 2022 13.2 10 Greenfield STO São Paulo Metro 17 Thales SelTrac 2022 17.7 24 Greenfield UTO Under construction Melbourne Cranbourne line, Pakenham line, Sunbury line, Metro Tunnel Bombardier CITYFLO 650 2023 115.8 70 Brownfield STO CBTC only available between West Footscray and Clayton stations São Paulo Metro Line 6 Nippon Signal SPARCS 2023 15 24 Greenfield UTO Under construction Tokyo Tokyo Metro Marunouchi Line[30] Mitsubishi ? 2023 27.4 53 Brownfield ? Tokyo Metro Hibiya Line ? ? 20.3 42 ? Seoul Sillim Line LS ELECTRIC LTran-CX 2023 7.8 ? ? ? JR West Wakayama Line ? ? 2023 42.5 ? Brownfield ? Kuala Lumpur Metro (LRT) Line 11, Shah Alam Line Thales SelTrac 2024 36 25 Brownfield UTO Marmaray Lines Commuter Lines Invensys Sirius ? 77 ? Greenfield STO Hong Kong MTR Kwun Tong line, Tsuen Wan line, Island line, Tseung Kwan O line Alstom-Hitachi Rail (formerly Thales) Advanced SelTrac 2026-2029 58.1 128 Brownfield STO & DTO New York City Subway IND Crosstown Line[31] Hitachi Rail (formerly Thales) SelTrac 2029 16 309[note 5] Brownfield STO Porto Metro [32] Alstom Cityflo 250 2024 3.0 18 Greenfield STO Ahmedabad MEGA Nippon Signal SPARCS ? 39.259 96 coaches (rolling stock) ? ? Baltimore Baltimore Metro SubwayLink Hitachi Rail STS CBTC 2025 24.8 78[note 7] Brownfield STO New railcars and signalling system undergoing testing, expected to enter service in mid-2025[33] Transport for London Elizabeth line Siemens Trainguard MT CBTC 2022 42 70 Brownfield STO Paddington to Abbey Wood / Stratford Jabodebek LRT Bekasi Line, Cibubur Line Siemens Trainguard MT CBTC[34] 2023 44.4 31 Greenfield DTO Oslo Metro All lines Siemens Trainguard MT CBTC 2025-2030 85 115 Greenfield (Fornebu Line) Brownfield (other lines) STO Being gradually rolled out throughout the system, first commissioned between Brattlikollen and Lambertseter on Lambertseter Line.[35][36] Atlanta MARTA All lines Stadler NOVA Pro CBTC 2024 77 354 Brownfield STO Hartsfield–Jackson Atlanta International Airport The Plane Train Alstom ? 2024 4.5 63 Brownfield UTO

## Notes and references

### Notes

1. **[^](#cite_ref-nyc_subway_canarsie_line_25-0)** This is the number of four-car train sets available. The BMT Canarsie Line runs trains with eight cars.

1. **[^](#cite_ref-nyc_subway_flushing_line_29-0)** This is the number of eleven-car train sets available. The IRT Flushing Line runs trains with eleven cars, though they are not all linked together; they are arranged in five- and six-car sets.

1. **[^](#cite_ref-30)** Work being done in phases; the main phase between [50th Street](/source/50th_Street_station_(IND_lines)) and [Kew Gardens–Union Turnpike stations](/source/Kew_Gardens%E2%80%93Union_Turnpike_station) was completed in 2022

1. **[^](#cite_ref-31)** Includes a 1.48 km "express bypass" where non-stopping [express trains](/source/Express_train) take a different route than stopping local trains.

1. ^ [***a***](#cite_ref-Crosstown-QBL_32-0) [***b***](#cite_ref-Crosstown-QBL_32-1) This is the number of four- and five- car sets to be equipped with CBTC; they will be linked up in sets of 8 or 10 cars each. The routes that use the Queens Boulevard and Crosstown lines are serviced by trains from [Jamaica Yard](/source/Jamaica_Yard) and [East New York Yard](/source/East_New_York_Yard).

1. **[^](#cite_ref-34)** Work being done in phases; the first phase is between [59th](/source/59th_Street%E2%80%93Columbus_Circle_station_(IND_Eighth_Avenue_Line)) and [High Street stations](/source/High_Street_station_(IND_Eighth_Avenue_Line)).

1. **[^](#cite_ref-39)** Total number of railcars ordered, service is typically operated using four-car trains.

### References

1. ^ [***a***](#cite_ref-IEEE1474_1-0) [***b***](#cite_ref-IEEE1474_1-1) [***c***](#cite_ref-IEEE1474_1-2) [***d***](#cite_ref-IEEE1474_1-3) [***e***](#cite_ref-IEEE1474_1-4) 1474.1–1999 – IEEE Standard for Communications-Based Train Control (CBTC) Performance and Functional Requirements.[\[1\]](https://ieeexplore.ieee.org/document/815310) (Accessed at January 14, 2019).

1. **[^](#cite_ref-2)** Wu, Qing; Ge, Xiahau; Cole, Colin; Spiryagin, Maksym; Bernal Arango, Esteban (2023-01-01). [*Communication based train control (CBTC): Train controller and dynamics*](https://acquire.cqu.edu.au/articles/conference_contribution/Communication_based_train_control_CBTC_Train_controller_and_dynamics/25806895). CQUniversity. [ISBN](/source/ISBN_(identifier)) [978-1-925627-79-4](https://en.wikipedia.org/wiki/Special:BookSources/978-1-925627-79-4).

1. ^ [***a***](#cite_ref-:1_3-0) [***b***](#cite_ref-:1_3-1) ["Thales awarded signalling contract for new Salvador metro"](https://www.thalesgroup.com/en/worldwide/transportation/press-release/thales-awarded-signalling-contract-new-salvador-metro). Thales Group. 2014-03-24. Retrieved 2019-05-09.

1. ^ [***a***](#cite_ref-SSR_4-0) [***b***](#cite_ref-SSR_4-1) Bombardier to Deliver Major London Underground Signalling.[\[2\]](http://www.bombardier.com/en/transportation/media-centre/press-releases/details?docID=0901260d80181411) Press release, Bombardier Transportation Media Center, 2011. Accessed June 2011

1. ^ [***a***](#cite_ref-mdm_5-0) [***b***](#cite_ref-mdm_5-1) *CITYFLO* 650 Metro de Madrid, Solving the capacity challenge.[\[3\]](http://Bombardier.com/files/en/supporting_docs/RCS_Case_Study_Metro_Madrid_en.pdf) [Archived](https://web.archive.org/web/20120330161346/http://bombardier.com/files/en/supporting_docs/RCS_Case_Study_Metro_Madrid_en.pdf) 2012-03-30 at the [Wayback Machine](/source/Wayback_Machine) Bombardier Transportation Rail Control Solutions, 2010. Accessed June 2011

1. ^ [***a***](#cite_ref-ttc-service-2019-03_6-0) [***b***](#cite_ref-ttc-service-2019-03_6-1) [***c***](#cite_ref-ttc-service-2019-03_6-2) ["Service Summary"](http://www.ttc.ca/PDF/Transit_Planning/Service%20Summary_2019-03-31.pdf) (PDF). *Toronto Transit Commission*.

1. ^ [***a***](#cite_ref-TTC-2017-01-18_7-0) [***b***](#cite_ref-TTC-2017-01-18_7-1) ["Modernizing the signal system: 2017 subway closures"](https://www.youtube.com/watch?v=FcGhkh10Q3I). [Toronto Transit Commission](/source/Toronto_Transit_Commission). January 18, 2017. Retrieved January 23, 2017. [video position 1:56]Trains will be able to operate as frequently as every 1 minute and 55 seconds instead of the current limit of two and a half minutes. [2:19]When installation is completed along the entire line in 2019, it will allow for as much as 25% more capacity. [2:33]ATC will come online on all of Line 1 in phases by the end of 2019 starting with the portion of Line 1 between Spadina and Wilson stations and with the Line 1 extension into [York Region](/source/York_Region) that opens at the end of this year.

1. **[^](#cite_ref-8)** Zhu, Li (5 November 2015). "1.2 Evolution of Train Signaling/Train Control Systems". In Yu, F. Richard (ed.). [*Advances in Communications-Based Train Control Systems*](https://www.google.com/books/edition/Advances_in_Communications_Based_Train_C/K0yNEQAAQBAJ). CRC Press. [ISBN](/source/ISBN_(identifier)) [978-1-351-23170-1](https://en.wikipedia.org/wiki/Special:BookSources/978-1-351-23170-1). Retrieved 1 June 2026.

1. **[^](#cite_ref-digitalradio_9-0)** Digital radio shows great potential for Rail [\[4\]](http://findarticles.com/p/articles/mi_m0BQQ/is_5_41/ai_80931845/) Bruno Gillaumin, International Railway Journal, May 2001. Retrieved by findarticles.com in June 2011.

1. **[^](#cite_ref-CBTC15_10-0)** ["Bombardier Marks 15th Anniversary of Its World-First Radio-Based, Driverless Rail Control System"](https://web.archive.org/web/20190122095005/http://www.marketwired.com/press-release/bombardier-marks-15th-anniversary-its-world-first-radio-based-driverless-rail-control-tsx-bbd.a-2246505.htm) (Press release). Bombardier Transportation. MarketWired. March 29, 2018. Archived from [the original](http://www.marketwired.com/press-release/bombardier-marks-15th-anniversary-its-world-first-radio-based-driverless-rail-control-tsx-bbd.a-2246505.htm) on January 22, 2019. Retrieved January 22, 2019.

1. **[^](#cite_ref-cbtcprojects_11-0)** CBTC Projects. [\[5\]](http://www.tsd.org/cbtc/projects/index.htm) [Archived](https://web.archive.org/web/20150614033641/http://www.tsd.org/cbtc/projects/index.htm) 2015-06-14 at the [Wayback Machine](/source/Wayback_Machine) www.tsd.org/cbtc/projects, 2005. Accessed June 2011.

1. ^ [***a***](#cite_ref-radiopdf_12-0) [***b***](#cite_ref-radiopdf_12-1) CBTC radios: What to do? Which way to go? [\[6\]](http://www.tsd.org/papers/CBTCRadios.pdf) [Archived](https://web.archive.org/web/20110728134242/http://www.tsd.org/papers/CBTCRadios.pdf) 2011-07-28 at the [Wayback Machine](/source/Wayback_Machine) Tom Sullivan, 2005. www.tsd.org. Accessed May 2011.

1. ^ [***a***](#cite_ref-:0_13-0) [***b***](#cite_ref-:0_13-1) [*Subset-023. "ERTMS/ETCS-Glossary of Terms and Abbreviations"*](https://web.archive.org/web/20181221134721/https://www.era.europa.eu/node/641/210_en). ERTMS USERS GROUP. 2014. Archived from [the original](https://www.era.europa.eu/node/641/210_en) on 2018-12-21. Retrieved 2018-12-21.

1. **[^](#cite_ref-iec_14-0)** IEC 62290-1, Railway applications – Urban guided transport management and command/control systems – Part 1: System principles and fundamental concepts.[\[7\]](http://webstore.iec.ch/webstore/webstore.nsf/ArtNum_PK/36384?OpenDocument) IEC, 2006. Accessed February 2014

1. **[^](#cite_ref-silent_15-0)** Madrid's silent revolution.[\[8\]](http://goliath.ecnext.com/coms2/gi_0199-12316026/Madrid-s-silent-revolution-the.html) in International Railway Journal, Keith Barrow, 2010. Accessed through goliath.ecnext.com in June 2011

1. ^ [***a***](#cite_ref-IRSE_16-0) [***b***](#cite_ref-IRSE_16-1) Semi-automatic, driverless, and unattended operation of trains.[\[9\]](http://www.irse-itc.net/index.php?option=com_content&view=article&id=85:semi-automatic-driverless-and-unattended-operation-of-trains&catid=36:published-itc-publications&Itemid=29) [Archived](https://web.archive.org/web/20101119000836/http://www.irse-itc.net/index.php?option=com_content&view=article&id=85:semi-automatic-driverless-and-unattended-operation-of-trains&catid=36:published-itc-publications&Itemid=29) 2010-11-19 at the [Wayback Machine](/source/Wayback_Machine) IRSE-ITC, 2010. Accessed through www.irse-itc.net in June 2011

1. **[^](#cite_ref-madridorg_17-0)** CBTC: más trenes en hora punta.[\[10\]](http://www.madrid.org/cs/Satellite?c=CM_InfPractica_FA&cid=1142612783785&idTema=1142598699551&language=es&pagename=ComunidadMadrid%2FEstructura&perfil=1273044216036&pid=1273078188154)[*[permanent dead link](https://en.wikipedia.org/wiki/Wikipedia:Link_rot)*] Comunidad de Madrid, www.madrig.org, 2010. Accessed June 2011

1. **[^](#cite_ref-18)** How CBTC can Increase capacity – communications-based train control. [\[11\]](http://findarticles.com/p/articles/mi_m1215/is_4_202/ai_75214234/?tag=mantle_skin;content) William J. Moore, Railway Age, 2001. Accessed through findarticles.com in June 2011

1. **[^](#cite_ref-19)** ETRMS Level 3 Risks and Benefits to UK Railways, pg 19 [\[12\]](https://web.archive.org/web/20110204131707/http://www.trl.co.uk/downloads/general/20100929_ERTMS_Level_3_Final_Report.pdf) Transport Research Laboratory. Accessed December 2011

1. **[^](#cite_ref-20)** ETRMS Level 3 Risks and Benefits to UK Railways, Table 5 [\[13\]](https://web.archive.org/web/20110204131707/http://www.trl.co.uk/downloads/general/20100929_ERTMS_Level_3_Final_Report.pdf) Transport Research Laboratory. Accessed December 2011

1. **[^](#cite_ref-21)** ETRMS Level 3 Risks and Benefits to UK Railways, pg 18 [\[14\]](https://web.archive.org/web/20110204131707/http://www.trl.co.uk/downloads/general/20100929_ERTMS_Level_3_Final_Report.pdf) Transport Research Laboratory. Accessed December 2011

1. ^ [***a***](#cite_ref-web.archive.org_22-0) [***b***](#cite_ref-web.archive.org_22-1) CBTC World Congress Presentations, Stockholm, November 2011 [\[15\]](https://web.archive.org/web/20120303131523/http://www.cbtcworldcongress.com/presentations) Global Transport Forum. Accessed December 2011

1. **[^](#cite_ref-23)** November 16; Staff, 2020 • METRO. ["Montreal Unveils first Alstom REM Car"](https://www.metro-magazine.com/10130428/montreal-unveils-first-alstom-rem-car). *www.metro-magazine.com*. Retrieved 2026-01-12.{{[cite web](https://en.wikipedia.org/wiki/Template:Cite_web)}}: CS1 maint: numeric names: authors list ([link](https://en.wikipedia.org/wiki/Category:CS1_maint:_numeric_names:_authors_list))

1. **[^](#cite_ref-24)** ["Mass transit signalling"](https://web.archive.org/web/20220101063113/https://rail.bombardier.com/en/solutions-and-technologies/signalling-and-infrastructure/mass-transit-signalling.html). 2022-01-01. Archived from [the original](https://rail.bombardier.com/en/solutions-and-technologies/signalling-and-infrastructure/mass-transit-signalling.html) on 1 January 2022. Retrieved 2024-11-26.

1. **[^](#cite_ref-26)** Stuart Green [@TTCStuart] (2021-10-02). ["This weekend's scheduled #TTC subway closure is now over and full service has resumed. Crews have completed the work on this phase of the new Automatic Train Control signaling system on Line 1. ATC now operating Vaughan MC to Eglinton"](https://twitter.com/TTCStuart/status/1444431122998431746) ([Tweet](/source/Tweet_(social_media))) – via [Twitter](/source/Twitter).

1. **[^](#cite_ref-27)** Fox, Chris (2019-04-05). ["New signal system is three years behind schedule and $98M over budget: report"](https://www.cp24.com/news/new-signal-system-is-three-years-behind-schedule-and-98m-over-budget-report-1.4367107). *CP24*. Retrieved 2019-04-10.

1. **[^](#cite_ref-Helsinki_STO_28-0)** Helsinki Metro automation ambitions are scaled back. [Urban Rail News](http://www.railwaygazette.com/news/urban-rail/single-view/view/helsinki-automation-ambitions-scaled-back.html) *[Railway Gazette International](/source/Railway_Gazette_International)* 2012

1. **[^](#cite_ref-thales-sg_33-0)** Cheng, Kenneth (2017-04-12). ["Full-day signalling tests on North-South Line to start on Sunday"](https://www.todayonline.com/new-nsl-signalling-system-be-tested-sundays-two-months). *TODAY Online*. Retrieved 2022-05-22.

1. **[^](#cite_ref-35)** ["Siemens Mobility and Stadler consortium wins contract to modernize and upgrade the Lisbon Metro"](https://web.archive.org/web/20240925154746/https://press.siemens.com/global/en/pressrelease/siemens-mobility-and-stadler-consortium-wins-contract-modernize-and-upgrade-lisbon?linkId=300000001147478) (Press release). Siemens Mobility. May 10, 2021. Archived from [the original](https://press.siemens.com/global/en/pressrelease/siemens-mobility-and-stadler-consortium-wins-contract-modernize-and-upgrade-lisbon?linkId=300000001147478) on September 25, 2024. Retrieved September 25, 2024.

1. **[^](#cite_ref-36)** [三菱電機、東京メトロ丸ノ内線に列車制御システム向け無線装置を納入](https://news.mynavi.jp/article/20180222-587991/) (in Japanese), [Mynavi Corporation](/source/Mynavi_Corporation), February 22, 2018

1. **[^](#cite_ref-37)** Artymiuk, Simon (March 7, 2023). ["MTA awards Crosstown Line CBTC contract to Thales and TCE"](https://www.railjournal.com/signalling/mta-awards-crosstown-line-cbtc-contract-to-thales-and-tce/). *International Railway Journal*. Retrieved August 4, 2024.

1. **[^](#cite_ref-38)** ["Alstom's leading urban signalling technology selected to enhance passenger connectivity on the Metro do Porto Pink Line in Portugal"](https://web.archive.org/web/20240524034020/https://www.alstom.com/press-releases-news/2024/3/alstoms-leading-urban-signalling-technology-selected-enhance-passenger-connectivity-metro-do-porto-pink-line-portugal) (Press release). Alstom. March 12, 2024. Archived from [the original](https://www.alstom.com/press-releases-news/2024/3/alstoms-leading-urban-signalling-technology-selected-enhance-passenger-connectivity-metro-do-porto-pink-line-portugal) on May 24, 2024. Retrieved September 25, 2024.

1. **[^](#cite_ref-40)** ["MDOT MTA to test CTBC system on Metro Subway stations"](https://www.masstransitmag.com/rail/railroad-signals-ptc-control-systems-and-products/press-release/55180169/maryland-transit-administration-mta-mdot-mta-to-test-ctbc-system-on-metro-subway-stations). *Mass Transit Magazine* (Press release). October 2, 2024. Retrieved December 15, 2024.

1. **[^](#cite_ref-41)** ["Len Kebut Pengerjaan Sistem Persinyalan Kereta Tanpa Masinis LRT Jabodebek"](https://www.len.co.id/len-kebut-pengerjaan-sistem-persinyalan-kereta-tanpa-masinis-lrt-jabodebek/). *PT Len Industri* (in Indonesian). 14 September 2021. Retrieved 2026-04-28.

1. **[^](#cite_ref-42)** Juven, Olav (2025-12-02). ["T-banen får nytt signalanlegg – skal bli flere tog og færre forsinkelser"](https://www.nrk.no/stor-oslo/t-banen-far-nytt-signalanlegg-_-skal-bli-flere-tog-og-faerre-forsinkelser-1.17675373). *NRK* (in Norwegian Bokmål). Retrieved 2025-12-30.

1. **[^](#cite_ref-43)** ["Siemens powers Oslo's metro digitalization with state-of-the-art ..."](https://press.siemens.com/global/en/pressrelease/siemens-powers-oslos-metro-digitalization-state-art-cbtc-system) *press.siemens.com*. Retrieved 2025-12-30.

### Further reading

- Wang, Chunjun (2026). [*Communications-Based Train Control, Volume 1: Foundations & Technical Architecture*](https://cbtcbook.com). Princeton, NJ: Independent. [ISBN](/source/ISBN_(identifier)) [979-8-258-54295-3](https://en.wikipedia.org/wiki/Special:BookSources/979-8-258-54295-3).

- Wang, Chunjun (2026). *Communications-Based Train Control, Volume 2: Operations, Deployment & Economics*. Princeton, NJ: Independent. [ISBN](/source/ISBN_(identifier)) [979-8-258-54528-2](https://en.wikipedia.org/wiki/Special:BookSources/979-8-258-54528-2).

- [Argenia Railway Technologies SafeNet CBTC](http://www.argeniarailwaytech.com)

- [Thales SelTrac(R) CBTC](https://web.archive.org/web/20140218094134/https://www.thalesgroup.com/en/content/seltracr-cbtc-communications-based-train-control-urban-rail)

v t e Railway signalling Block systems Absolute block signalling Automatic block signaling Centralized traffic control Communications-based train control Direct traffic control European Train Control System Moving block Radio Electronic Token Block Token Track Warrant Control Train order operation Signalling control Block post Integrated Electronic Control Centre Interlocking Lever frame Rail operating centre Solid State Interlocking Westlock Interlocking Signals Application of railway signals Cab signalling North American railroad signals Railway semaphore signal Train detection Axle counter Track circuit Track circuit interrupter Treadle Train protection Advanced Civil Speed Enforcement System ALSN ASFA ATACS ATMS Automatic train control Automatic train operation Automatic train protection Automatic Train Protection (United Kingdom) Automatic train stop Automatic Warning System Automatische treinbeïnvloeding Balise Catch points Chinese Train Control System Cityflo 650 CBTC Continuous Automatic Warning System Contrôle de vitesse par balises EBICAB IIATS Integra-Signum Interoperable Communications Based Signaling Crocodile Korean Train Control System Linienzugbeeinflussung Positive Train Control Pulse code cab signaling Punktförmige Zugbeeinflussung RS4 Codici SelTrac Sistema Controllo Marcia Treno SACEM Slide fence Train automatic stopping controller TMACS Train Protection & Warning System Train stop Trainguard MT Transmission balise-locomotive Transmission voie-machine Crossing signals Level crossing signals Crossbuck Wigwag E-signal Wayside horn Manufacturers Adtranz Alstom AŽD Praha Federal General Electric GRS Griswold Hall Hitachi Hyundai Rotem Magnetic Progress Rail Safetran Saxby Siemens Smith and Yardley Thales Union Switch Westinghouse Brake & Signal Westinghouse Rail Systems Organisations AAR AREMA ERA FRA HMRI IRSE Transport Canada UIC By country Australia Bavaria Belgium Canada China Finland France Germany Greece Italy Japan Netherlands New Zealand North America Norway Poland Sweden Switzerland Thailand United Kingdom

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Adapted from the Wikipedia article [Communications-based train control](https://en.wikipedia.org/wiki/Communications-based_train_control) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Communications-based_train_control?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.