Rail Vehicle Capability

EMTRAC Transit Signal Priority

Transit Signal Priority (TSP)

Trains equipped with the EMTRAC system are able to automatically request priority through signalized intersection. This is accomplished through the utilization of reliable GNSS technology and encrypted FHSS radio.

Transit Signal Priority with EMTRAC TSP

Signal Priority without Traffic Disruption

As a train approaches an equipped intersection, it passes through geographically-defined detection zones, which prompt the EMTRAC system to transmit a priority request to the corresponding traffic-signal controller.

The EMTRAC system completes this request without any driver interaction. Additionally, signal priority control may be configured based on route-schedule adherence, passenger loads, time of day, or other factors.

  • Conditional Signal Priority may be configured so equipped vehicles request priority only when specific, agency-defined conditions are met. As an example, a train can request priority only when it is five or more minutes behind schedule.
  • Trains may utilize EMTRAC ETA technology to calculate intersection arrival times and update traffic-signal controllers of these arrival times. Updated ETA times are calculated based on current travel conditions (U.S. Patent No. 8,878,695).
  • The EMTRAC Systems Manager software enables easy customization of train and intersection activity and response. For example, trains used for game-day sporting events may be configured to hold priority requests for longer time periods.
  • The EMTRAC Central Monitor application provides activity logs and reports, showing detailed vehicle and intersection activity by date and time.
  • Equipped trains may be configured to request priority at earlier start points to allow traffic controllers adequate phasing time during peak-period rush hours.
  • In addition to the well documented— benefits of Transit Signal Priority, the EMTRAC system helps reduce occurrences of uncoordinated signals and the resulting traffic disruptions.
  • Labor time spent on installation and maintenance is significantly less than with other priority systems.
  • Compatible with both leading-edge and legacy controllers while offering the most advanced TSP features available.
  • Enables transit agencies to improves schedule adherence and headway times by requesting signal priority only when needed (for example, when behind schedule).
  • Transit personnel are able to observe vehicle progress and activity with the EMTRAC Central Monitor software.
Headway Maintenance

Train bunching—a trailing train catching up to a lead train—is a continual challenge for transit agencies. It is also a leading complaint of regular transit riders and a headache for those operating and managing transit services.

Headay maintenance is simplified with the EMTRAC system. Signal priority may be conditional—based on the amount of time since priority was last granted to a train traveling in the same direction. Alternately, equipped trains may utilize virtual moving blocks to notify train operators when a particular action should be taken (for example, trailing trains may slow to a designated speed or leading trains may operate in express or skip-stop mode) until the desired headway is re-acquired.

Information Sheets



Automatic Vehicle Location (AVL)

Supervisory personnel are able to remotely monitor real-time train and intersection activity with EMTRAC Central Monitor software.

Transit Control Center with EMTRAC Central Monitor - Automatic Vehicle Location System

EMTRAC Central Monitor Displaying AVL Maps

Equipped trains continuously report location and activity data to EMTRAC detectors, which are network connected and located in wayside cabinets. Central workstations display this data while showing train movement on a real-time map display. Central Monitor also records this data in detailed logs for later review.

Because the AVL system uses the same EMTRAC components as those used for basic Transit Signal Priority, the system is a cost-effective way to provide accurate and reliable activity monitoring.

  • Automatically locate specific trains, intersections, and rail workers with the click of a mouse.
  • Connect to signals and switches to enable display of current signal and switch states on map.
  • When specified events occur (such as speed violations), the system can automatically alert designated personnel—as they occur.
  • The system may be configured to automatically generate reports, which are then archived and emailed to designated personnel.
  • Activity logs may be automatically transferred and saved to the network while trains are at rail yards.
  • View Connectivity Logs, which show changes in network-connectivity status to help identify possible network issues.
  • Monitor signal-controller responses to priority requests to help verify proper system functionality.
  • Expandability: AVL components may be added to existing EMTRAC system as agency budgets and schedules allow.
  • Ease of Installation: Minimal additional hardware is required because the AVL system interfaces with existing EMTRAC system components (such as those used for Transit Signal Priority or to implement elements of Positive Train Control).
  • Flexibility: Specific train classes (such as Light Rail Vehicles or Commuter Vehicles) may have individual detection zones assigned to them, which require that custom conditions be met before Transit Signal Priority is requested.
  • Security: The AES-encrypted FHSS radio signals utilized by the EMTRAC system offer superior range and unmatched security.
  • Accuracy: The advanced GNSS and inertial positioning ensures precise train location reporting—even in adverse conditions and environments.

Information Sheets



Positive Train Control

The EMTRAC PTC System combines precise positioning technology with secure FHSS radio communication to incorporate key elements of Positive Train Control. The EMTRAC system includes Stop-Bar Overrun, Overspeed Protection, and Collision Avoidance—while also offering additional capability as described below.


When an equipped train exceeds defined safety thresholds, the EMTRAC system alerts train operators and central personnel. For all instances of exceeded safety thresholds, the EMTRAC system may also alert the train operator of the event on the in-cab Control Head.

If additional thresholds are reached, the trains can be set up to automatically slow down and/or stop while an alert is sent to all other trains.

The Central Monitor software saves a detailed log of designated events and train activity and may be configured to email these events to designated personnel on a periodic basis.

The EMTRAC system requires no costly in-track circuits to install or maintain, and it accurately reports train locations, even in difficult urban-canyon environments.

Overspeed Protection
EMTRAC Central Monitor Displaying Stop-Bar Overrun Alert

The Control Head Alerts Operators of Excessive Speed

The EMTRAC system uses "Virtual Fixed Blocks" to designate allowable speeds for specific segments of track. These blocks can be customized on the fly to allow for special events or temporary speed restrictions.

When equipped trains exceed defined speed limits, both operations center personnel may be notified of the event by the Central Monitor software, which also saves a detailed log of designated events and train activity. Central Monitor may also be configured to email these events to designated personnel on a periodic basis.

As with all other defined safety thresholds, train operators may be alerted about excessive speed by the in-cab Control Head.

Collision Avoidance
EMTRAC Central Monitor Displaying Stop-Bar Overrun Alert

EMTRAC Technology Helps Ensure Open Rail Lines

"Virtual Moving Blocks" are used to ensure that trains adhere to agency-defined block spacing. These moving blocks travel with their assigned rail vehicles, and the block lengths adjust based on train speed (or as calculated by braking algorithms).

When the EMTRAC system determines that two equipped trains are within the same block, train operators and central personnel are immediately notified—and further actions may be taken such as automatic slowing (by either ceasing propulsion, braking, or a progressive combination).

For more information about EMTRAC Collision Avoidance, please watch the video above.

Stop-Bar Overrun
EMTRAC Central Monitor Displaying Stop-Bar Overrun Alert

EMTRAC Central Monitor Showing a Stop-Bar Overrun Alert

The EMTRAC system is capable of notifying designated personnel when trains run past precise stop locations, for example, at stations, intersections, and crossings.

Due to the urban environments where transit agencies seek to ensure pedestrian safety, accurate stop monitoring can be difficult to achieve. The EMTRAC system has proven its ability in the most difficult environments.

  • Central computers display real-time status and locations for all equipped vehicles.
  • Generate detailed status and activity logs, save them as reports, and export them as spreadsheet files.
  • Trains are equipped with Control Heads to visually and audibly alert operators of exceeded safety thresholds.
  • Interface with other EMTRAC-equipped vehicles (such as buses or fire-department vehicles) to help avoid collisions with non-rail vehicles.
  • EMTRAC software displays graphical locations in map view, aerial-photo view, or native EMTRAC view. It also enables the user to automatically locate specific trains and blocks with the click of a mouse.
  • EMTRAC Vehicle Computer Units can be set up to perform periodic diagnostic checks to ensure proper performance.
  • EMTRAC software enables operations personnel to record and save train activity for later review of key events.
  • Flexibility: Speed and distance thresholds are easily configured and implemented to allow for special events or temporary speed restrictions. Thresholds may include maximum authorized speeds, minimum allowed distances from other trains (as determined by speed or braking algorithms), and switch confirmation.
  • Reliability: Wireless communication is not hampered by adverse conditions, and the radio range allows for relatively few detector units.
  • Precision: Determine which tracks a particular train is on with position accuracy of +/- 24-inches or less.
  • Low Maintenance: Interface with existing switches and circuits without requiring costly in-track installations.
  • Timeliness: Improve route-schedule adherence by enabling designated trains (such as those on express routes) to request priority through signalized intersections.

Information Sheets



Automatic Logs & Updates

With the EMTRAC system. transit agencies are able to automatically transfer vehicle activity logs—and upload database and firmware updates—while equipped trains are at rail operation centers, maintenance facilities, or other locations.

EMTRAC Interrogator System - Download TSP Activity Logs

Automatic Transfer of Logs at Rail Operations Center

As equipped trains return to rail yards, the EMTRAC Interrogator system utilizes secure FHSS radio to transfer activity logs from onboard Vehicle Computer Units (VCUs). The Central Monitor server accesses this data where it can be remotely viewed by authorized personnel.

When train configurations are updated, or if firmware updates are available, the Interrogator system distributes the updates to the proper vehicles, and monitoring personnel are able to check update progress as it occurs.

  • Automatic Transfer & Update: Wirelessly transfer activity logs from equipped vehicles, and automatically transfer database or firmware updates to onboard VCUs.
  • Stable Communication: In cases of network interruption, data is not lost, and data transfers resume from the point of interruption.
  • Limitless Memory: Because the EMTRAC-system server stores activity logs, the onboard VCUs are able to continually save new log entries.
  • System Monitoring: Agency personnel can monitor network-connection status and history (between Interrogator and EMTRAC components as well as between server and Interrogator), and current radio-signal strength.
  • Auto-Notifications: The Central Monitor software may be configured to periodically email activity logs to designated agency personnel.
  • Low Profile: Communication with onboard VCUs is all wireless. The EMTRAC Interrogator Kit requires only 120 VAC power and Ethernet for external connections.
  • Timeliness: Data is transferred rapidly using high communication rates.
  • Flexibility: The EMTRAC Interrogator Kit may be mounted on a wall, pole, or other structure. Multiple antenna options provide reliable communication—even in locations with high interference.

Information Sheets