Positive Train Control

 Positive Train Control

Positive Train Control (PTC) is an advanced system designed to prevent train-to-train collisions, over-speed derailments, unauthorized incursions into work zones, and train movement through switches left in the wrong position. PTC monitors and, if necessary, controls train movement in the event of human error. 


1990: The National Transportation Safety Board in 1990 introduced its now-annual list of “most wanted” transportation safety recommendations.  A safety system referred to as positive train control was included on that inaugural list, and thereafter, until Congress passed the Rail Safety Improvement Act in 2008.

1994: An analysis undertaken by the FRA at the behest of Congress showed that the safety benefits of PTC did not justify requiring it.

2004: Ten years later, in response to a request from the Senate Appropriations Committee, the acting administrator of the Federal Railroad Administration submitted an updated analysis of the cost and benefits of positive train control and related systems, this time taking into account advances in technology and system savings, to include an analysis of the business benefits, such as improved traffic flow, a modal shift of goods from trucks to rail, and the concurrent environmental benefits. 

The report stated, in part:

  • There is no vendor offering immediate sale of such a system.

  • Predicted eight years for development and installation if a funding mechanism were already in place.

  • If the railroads had thought there were business benefits they would have already invested in enhancing operations through PTC.

2008: In September of 2008, a passenger to freight train collision in Chatsworth, California left 25 people dead and 135 injured.  The engineer at fault in that incident was found to have been distracted by texting.

Within a month, Congress had passed the Rail Safety Improvement Act (RSIA), requiring certain railroads to install communications-based train control systems to overcome human error or distraction. The mandate required positive train control (PTC) systems to be implemented – installed and interoperable - by December 31, 2015.  There was no federal funding mechanism envisioned as part of the legislation.

2010:  The FRA issues final guidance to the railroad industry for PTC implementation as a result of the RSIA.

As defined by the Federal Railroad Administration, “PTC uses communication-based/process-based train control technology that provides a system capable of reliably and functionally preventing train-to-train collisions, overspeed derailments, incursions into established work zone limits, and the movement of a train through a main line switch in the wrong position.”

It must be noted that PTC does not prevent grade crossing or trespasser incidents, nor does it initiate in-terminal stops.  These are covered in more detail HERE.


With the passage of the Rail Safety Improvement Act, 41 commuter, Class 1 freight, and short line railroads were required to install a communications-based train control technology on their trains, and 60,000 miles of track would need to be equipped with wayside components.  

At the time it was estimated that installing PTC systems would cost the publicly-funded commuter railroads $2 billion to meet the congressional mandate.  But PTC was still not yet a proven, nor an off-the-shelf technology.  Moreover, system components had to be customized to every individual railroad’s unique operating environment.

Early implementation progressed in fits and starts, with unanticipated challenges interrupting the timeline anticipated by Congress.

  • FRA guidance: More than a year after Congress passed the RSIA, FRA issued its guidance document in January 2010.

  • Access to spectrum: The private Class 1 freight railroads formed PTC220 LLC and bought up frequency to meet their spectrum needs; meanwhile, the publicly-funded passenger railroads were struggling to find spectrum to purchase on the open market.  Repeated pleas to the FCC to recognize PTC’s spectrum requirements as safety critical went unheeded. 

  • Funding challenges: Without federal resources, public agencies were forced to reevaluate their capital plans to prioritize PTC over locally identified state of good repair/critical safety needs.  

  • Access to qualified suppliers: Funding/financing challenges for publicly-funded commuter railroads delayed their access to the already limited number of qualified suppliers and system integrators with the expertise to deliver PTC systems.


At the request of Congress, the US Government Accountability Office (GAO) undertook a series of industry reviews to evaluate the railroads’ implementation progress and the efficacy of federal oversight.  

Two years after the RSIA was passed, in 2010, the GAO cited the following challenges and obstacles:

  • Software to test components remains in development 

  • Publicly-funded commuter railroads may have difficulty covering the $2 billion that PTC is estimated to cost them (*that figure has since doubled) 

  • The cost of PTC alone could create delays if funding is not available 

  • The cost of PTC could require that railroads divert funding from other critical areas, such as maintenance 

  • Other critical needs may go unmet if funding is diverted to pay for PTC 

And, in 2013, two years in advance of the 2015 deadline, in another report the GAO noted:

  • PTC components…are still under development 

  • The need to integrate PTC components and field test the system is a time and resource consuming process 

  • Without adequate testing, PTC systems might be more prone to reliability issues 

  • In attempting to implement PTC by the 2015 deadline, railroads could be making choices that could introduce financial and operational risks 

  • Railroads that operate as tenants on host rail lines must wait until the host fully equips the lines they operate on

  • The ability of railroads to meet the (2015) deadline may be affected by the interoperability of their PTC system with those of other railroads and whether they can obtain final system approval by the FRA

  • Development of a major component of the Interoperable Electronic Train Management System, being installed by the largest railroads, continues to be delayed

  • Smaller railroads have been challenged in obtaining PTC support and components due to the limited number of vendors

  • Some host railroads have multiple tenant railroads and the host railroad must work with tenants to determine if the tenants should equip with PTC. One large freight railroad said it must make this determination for 260 tenants. Railroads must ensure their systems are interoperable, a task that can be challenging when multiple railroads are involved.