Rail-System Components

EMTRAC Transit Signal Priority

The EMTRAC system consists of three major components—vehicle equipment, wayside equipment (installed at intersections or other locations along the right-of-way), and the software used to configure and monitor the system.

Vehicle Equipment

EMTRAC Vehicle Computer Unit

VCU and Dual RF/Satellite-Positioning Antenna

Vehicle Computer Unit (VCU)

EMTRAC-equipped trains carry a compact, yet rugged, Vehicle Computer Unit (VCU), which is connected to a dual RF/satellite-positioning antenna that receives precise location data and transmits safety alerts and priority requests to wayside equipment via secure radio. The VCU tracks train location with precision, and its superior range ensures reliable reception—even in adverse conditions.

Trains with the EMTRAC system transmit priority requests or safety alerts to equipped intersections when passing through pre-defined detection zones. The wayside signal-control cabinet contains an EMTRAC Priority Detector, which relays priority requests to the signal controller.

  • 900 MHz, frequency-hopping spread spectrum radio with secure, 256-bit AES encryption
  • Typical transmission range over 3,000 feet, enabling detection zones of the same length
  • Integrated computer board contains an ultra-fast processor and superior memory, while the MicroSD-card offers additional activity-log storage capability
  • Operates off nominal 10 to 40-volt DC power source with a maximum current of 500mA
  • Capable of communication through Ethernet, RS-232, or wireless connection
  • Sends four main directional codes and four auxiliary codes, while supporting up to 16 inputs and outputs in any combination
  • Capable of storing up to 5,000 detection zones
  • Ability to accept multiple inputs to prompt priority requests, including train-door status, schedule adherence, passenger count, and other inputs
  • Time-out feature is configurable to cease transmissions after a designated amount of inactivity
EMTRAC Onboard Control Head

EMTRAC Control Head Models

Control Head

The Control Head enables train operators to monitor system activity in real time. In addition to other features, operators may be alerted when right-of-way personnel are on upcoming tracks and when there is immediate potential for collision with other equipped trains.

The Control Head is available in three models. The LED model (upper left) displays basic activity information. The Touchscreen model (upper right) displays both train activity and safety alerts, such as collision-avoidance alarms. The Programmable model (bottom) displays train activity and safety alerts, and may be used to change VCU configuration settings.

  • Indicates that the VCU is 1) actively receiving satellite signals, 2) the train is currently in a detection zone, 3) the VCU is actively requesting signal priority, or 4) the priority request has timed out
  • May switch system to standby mode for monitoring/testing
  • Enables operator to reset timed-out priority requests
  • Warns operator of potential collisions with EMTRAC-equipped vehicles or personnel, as well as other designated alerts, such as if the train is exceeding posted speed limits (Touchscreen and Programmable models)
  • May indicate that signal priority has been granted
  • Displays estimated time of arrival to defined points (Touchscreen and Programmable models)
  • Safety: Reduce the chance for accidents by pro-actively alerting drivers of potential hazards.
  • Efficiency: The Programmable model is equipped with a USB port, enabling agency personnel to load only intersections and detection zones for specific routes. It is also equipped with an Ethernet port, which may be used to download data or upload firmware updates.
  • Reliability: The Touchscreen model enables operators to reset timed-out requests to help clear signals even in gridlock conditions.
  • Flexibility: The EMTRAC system may be installed on any train or vehicle type (including LRVs, commuter trains, buses, first-response vehicles, snow plows, etc.), with control heads installed on select vehicles.

Wayside Equipment

Wayside equipment includes the cabinet-mounted Priority Detector, the pole-mounted Omni-Directional Antenna, Personal Notification Units (PNUs), and the optional Interrogator Kit, which automatically downloads activity logs and installs firmware updates as needed.

EMTRAC TSP/EVP Priority Detector

EMTRAC ST-9283 Priority Detector

Priority Detector

The EMTRAC Priority Detector consists of a 900-MHz spread-spectrum transceiver and a single-board computer integrated in a dual-card assembly that plugs into the signal-control cabinet’s detector rack or on an interior shelf.

The Priority Detector is compatible with NEMA, 170/2070, Caltrans, ITS, and custom cabinets. It support up to 16 inputs, allowing for calls to be received for multiple phases from EMTRAC Vehicle Computer Units.

The EMTRAC Omni-Directional Antennas provide 2.15 dBi gain performance. The antennas are ground-plane independent and can be mounted in a variety of locations. Antenna wiring is encapsulated to provide exceptional resistance to extreme weather conditions.

  • Includes serial RS-232 or Ethernet communications to enable remote monitoring of system activity and configuration of EMTRAC equipment through the existing rail or traffic network
  • Supports up to 16 inputs and 16 outputs, with one auxiliary output configurable as a satellite-timing signal
  • Logs up to 5,000 locally-stored events (up to 10,000 events with removable memory)
  • Four main directional outputs and up to 12 auxiliary outputs are provided, with each input and output signal optically isolated for 2,500 volts
  • Operates on 120 VAC with its own power supply, and fits NEMA, 170/2070, ITS, Caltrans, and custom cabinets
  • Includes indicator lights for power on, signal received, active-output by priority, and direction of signal or channel
  • Includes toggle switches to send output in either Priority 1 or Priority 2 mode, allowing manual testing of detector function and controller response. The Standby/Active switch enables testing and configuration without affecting the live signal
  • Compatible with all major brands of NEMA and 170/2070 controllers
EMTRAC Vehicle Interrogator Kit for TSP/EVP

EMTRAC Vehicle Interrogator Kit

Interrogator Kit

The EMTRAC Interrogator Kit enables agencies to automatically transfer activity logs from EMTRAC-equipped trains and to upload firmware and database updates to these same onboard units.

As equipped trains return to rail operations centers, the Interrogator utilizes secure FHSS radio to download activity logs from onboard EMTRAC units. This data is forwarded to a server running EMTRAC Central Monitor, where it can be viewed by agency personnel.

The EMTRAC Interrogator may be installed at rail operation Centers, bus garages, fire stations, municipal-vehicle garages and lots, as well as maintenance facilities.

  • Automatic Retrieval and Update: Wirelessly download activity logs from EMTRAC components, and automatically upload firmware or database updates to units that have not yet received the update. Operations personnel may also view data-transfer status as they occur.
  • Auto-Notifications: The EMTRAC software may be configured to email periodic activity logs to specified agency personnel.
  • System Monitoring: The EMTRAC software enables agency personnel to monitor connection status and history (between server and Interrogator as well as between Interrogator and other EMTRAC components), and current RF signal strength.
  • Communication Stability: Data is not lost in cases of network interruption, and data transfers resume from the point of interruption.
  • Minimal Wired Connections: For external connections, the EMTRAC Interrogator Kit requires only 120 VAC power and Ethernet. All communication with EMTRAC vehicle components is performed wirelessly.
  • Limitless Memory: By transferring activity logs to the system server, onboard EMTRAC components are able to continually store new log entries.
  • Timeliness: High transfer rates enable data transfers that take a relatively short period of time, offering many options for where to mount the Interrogator—such as near maintenance or washing stations.
  • Flexibility: The EMTRAC Interrogator may be mounted on wall, pole, or other structure, and multiple antenna options allow for reliable communication in even high-interference environments.

Worker Equipment

Personal Notification Unit (PNU)

As the number of rail lines through metro areas increase, so does the potential for pedestrian accidents—and wayside rail workers are often in the most vulnerable locations.

EMTRAC Universal Phase Selector - Dual RF/Optical Priority Detector

Personal Notification Unit

By utilizing precise satellite positioning and secure FHSS radio, the EMTRAC Personal Notification Unit (PNU) alerts rail workers when an approaching train is within a specified distance. When the train reaches this distance, the PNU flashes an ultra-bright LED, sounds a pulsed alarm, and/or vibrates to alert the worker of the approaching train.

The PNU may be carried on a belt or in a vest pocket and includes multi-constellation satellite and inertial navigation, a UHF transceiver, and a panic button that enables workers to notify team members of critical situations.

Each PNU has its own ID, which may be assigned based on worker IDs. The PNU logs worker activity, alert details, and the ID and speed of approaching trains. Alerts may also be customized to activate based on the Estimated Time of Arrival (for the train to reach the worker). The PNUs ship with charging components and contains a 12-hour lithium-ion rechargeable battery to ensure reliable operation through work shifts.

Information Sheets



System Software

EMTRAC Central Monitor - Automatic Vehicle Location for Transit Signal Priority and Emergency Vehicle Preemption

Central Monitor Real-Time Activity Map

Transit agencies are able to take full control of their priority system by utilizing the EMTRAC software.

This software includes EMTRAC Systems Manager, which is used to configure all of the components of the EMTRAC system. It is where you define the trains, crossings or intersections, and zones that will be utilized for your system—and where you specify how the train and wayside equipment will respond in different scenarios. While the EMTRAC system is relatively simple to set up, it is also robust enough to handle complex applications.

EMTRAC Central Monitor is an Automatic Vehicle Location (AVL) service that displays precise train and worker activity and much more. Additional Central Monitor capabilities are listed below.

  • Map display of rail lines and city streets, showing real-time location and activity for all equipped trains.
  • Ability to monitor train "events" by user-definable types. For example, when used to monitor light rail activity, the system can be set up to log stop-bar overruns (as described in the Rail Line Safety video).
  • Audible and pop-up alarms notify operations center personnel of critical events (such as a light rail vehicle on the wrong tracks).
  • Automatically generate user-definable reports, which can be automatically archived and/or emailed at defined intervals.
  • Verify proper system functionality by monitoring signal-controller responses to priority requests.
  • Remotely check EMTRAC system diagnostics to verify proper functionality.
  • Detect and confirm proper rail crossing-gate closure. If a gate fails to close, an alarm may be sent to the operations center and vehicle driver.
  • Ease of Monitoring: Know where equipped trains and workers are in real time.
  • Low-Maintenance: Reliable train positioning and RF communication requires no costly in-track loops or switches.
  • Reporting: Generate detailed status and activity reports, as well as connectivity reports.
  • Safety: Alert monitoring personnel about potentially unsafe train activity in real time.
  • Flexibility: Customize detection zones and necessary parameters to transmit desired train-activity data and safety alerts.
  • Timeliness: Improve schedule adherence by requesting signal priority when agency-specified conditions are met.
  • Security: Frequency-hopping spread spectrum radio signal has expansive range and utilizes AES encryption.
  • Accuracy: Monitor train activity with precise and current location data.