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Metrolink Positive Train Control, Southern California

Positive Train Control

Positive Train Control / Collision Avoidance Technology

Positive train control (PTC) is collision avoidance technology that monitors and controls train movements. It is intended to prevent train-to-train collisions, overspeed derailments, and movement of trains through switches left in the wrong position, as well as prevent train incursions in to work areas. To improve railroad safety in the United States, federal legislation mandates that passenger railroads and large freight railroads (Class I railroads) install positive train control by December 31, 2015, on all main line track where intercity passenger railroads and commuter railroads operate, as well as on lines carrying hazardous materials.

A Solution Partner to Fast-Track Positive Train Control

In response to the Railroad Safety Enhancement Act of 2008, Parsons, with our worldwide experience and expertise, developed a compelling strategy to help the owners and operators of America’s railroads achieve their PTC compliance requirements in a cost-effective and timely manner. This strategy is flexible, depending on whether the railroad needs a full turnkey solution or program-specific elements that will minimize costs and ensure that mandatory deadlines are met.

Parsons is vendor-neutral, with no predetermined product focus on any particular technology and maintains the ability to select the most cost-effective system for customers pursuing PTC. We will team with vendors whose products are proven and most compatible with our customer’s railroad, delivering the components necessary for an FRA-compliant PTC solution that is based on a comprehensive project schedule and is interoperable with tenant and host railroads.

Caldecott Tunnel

On-board testing and commissioning

Design-Build Project Approach / System Integrator

Parsons has more than 60 years of experience working with all of the key vendors and suppliers of safety-critical and vital systems for railroads and transit systems. Our ability to manage, design, construct, and integrate the entire infrastructure required of PTC is essential to ensure that the established interoperable train control standards are met.

As the prime contractor leading vendor/integrator teams, Parsons manages the overall program as well as design, testing, systems integration, and commissioning services. In addition, Parsons has led the overall radio frequency infrastructure development for clients, managing the development of the network management system, and replacing the dispatching system.

Typical PTC implementation program consists of five primary subsystems:

  • Office (back-office servers, computer-aided dispatching, and customer information system enhancements)
  • Communication network
  • Onboard segment
  • Wayside segment
  • Employee-in-charge terminals
Caldecott Tunnel

PTC Lab used for testing 

It also includes integration, testing, and commissioning of all of the various products and systems to provide a fully functional, FRA certified, interoperable PTC system.

To ensure that the overall system fulfills its intended purpose, Parsons built a PTC lab to test and integrate components as they are developed. Our PTC lab is the first among commuter agencies to integrate and test components developed by multiple vendors in order to ensure compatibility and overall system functionality. Parsons has two PTC labs for testing components and subsystems, and is one of two non-railroad entities to operate such a lab.


Interoperability between rail companies is a key challenge because freight and passenger trains share tracks and therefore need to exchange railroad specific information to trains that cross operating boundaries. Parsons clients share track with most of the Class I Railroads, so any given PTC system must be fully interoperable with the PTC system being used by the freights. 

PTC Firm of Choice


  • Project Location:  Los Angeles, California
  • Project Size:  $124 Million
  • Project Description:  Turnkey Vendor/Integrator (Design/Build)
  • Design, fabrication, procurement installation, testing, training, documentation and support of the train control system to prevent train-to-train collisions, over speed derailments, incursions into established work zone limits, and the movement of a train through a main line switch in improper alignment. The PTC system covers 512-track miles and consists of five (5) primary subsystems including: 1) Office (BOS & CAD); 2) Communication; 3) On-board; 4) Wayside; and 5) Employee-in-Charge (EIC).
  • Unique challenges:  First PTC system implementation on a commuter railroad with an accelerated schedule. Providing Interoperable train control between Metrolink and UP/BNSF, Introduction of advanced technology without impact to performance
  • Benefits: New state of art safety system; New CAD dispatch system; Improved systems reliability


  • Project Location:  San Francisco, California
  • Project Size:  $138 Million
  • Project Description:  Design and Integrate a new PTC system for the Caltrain system. Upgrading the wayside with PTC compliant signal control, installing a 52 mile fiber optic backbone, equipping the existing rolling stock with new onboard computers from GETS, and providing a new Back up Control Center.
  • Unique challenges:  First PTC system with true interoperability between two different signal control systems. Parsons is providing the ITCS onboard system for Caltrain trains while tenant trains will be equipped with an I-ETMS solution. Benefits: In addition to the improved safety benefits from PTC, the system is also being designed to manage station stopping and grade crossing control to improve operational performance.


  • Project Location: State of New Jersey
  • Project Size: $156 Million
  • Project Description: Turnkey contract for complete design, manufacture, test and safety certification of FRA compliant positive train control system
  • Unique challenges: Providing Interoperable operations and technology with other operators on the Northeast Corridor. Also requires design of independent RF systems for commuter and freight operations.
  • Benefits: Enhanced passenger and track worker safety with Stop enforcement overlay; Complete replacement of onboard train control systems on 500 vehicle fleet; Network connectivity and diagnostics to over 100 wayside control points; Upgraded computer dispatch system for entry and tracking of speed restrictions; Improved system reliability

  • Amtrak – IETMS Phase I

    • 225 Track miles
    • 150 Amtrak daily train movements (over 1000 NJT, LIRR into Penn Station)
    • Interoperability w/ CSX, NS, MARC, VRE, Conrail

    Parsons  General Engineering

  • Developing Interoperable Train Control interoperability for Northeast Corridor (NEC)
  • Perform systems integration