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Policy Issues


Positive Train Control

The nation’s freight rail industry remains on schedule for having Positive Train Control (PTC) fully implemented across the country and in accordance with the extension passed by Congress last year.

PTC is a set of highly advanced technologies designed to make freight rail transportation—already one of the safest U.S. industries—even safer by automatically stopping a train before certain types of accidents occur. In 2008, Congress passed an unfunded mandate requiring America's privately owned railroads to finance, develop, install and test this unproven technology across 60,000 miles of the nation's rail network by December 31, 2015.​

From the outset, the 2015 deadline proved arbitrary and unworkable, and was compounded by technical and legal complexities. Railroads advised Congress for years that they would not be able to meet the deadline. As the deadline approached, railroads and freight rail customers made it clear that there would be serious consequences for the nation if the deadline was​​ not extended.

In response, Congress passed H.R.3819 - Surface Transportation Extension Act of 2015, which provides a three-year extension to 2018 for the installation of PTC. The new law also allows up to two additional years to finalize full implementation and testing of PTC provided the railroads meet specific benchmarks. Railroads are fully committed to meeting these new requirements and will regularly report to the US Department of Transportation on their progress.


How PTC Works

Current Progress & Timeline


PTC is an unprecedented set of highly advanced technologies designed to automatically stop a train before certain types of accidents occur. Specifically, as mandated by law, PTC is being developed to prevent:

​​- Train-to-train collisions

- Derailments caused by excessive speed
- Unauthorized incursions by trains onto sections of track where maintenance activities are taking place
- Movement of a train through a track switch left in the wrong positions

PTC will not prevent accidents caused as a result of:     

- Track equipment failure
- Improper vehicular movement through a grade crossing
- Trespassing on railroad tracks
- Some types of train operator error


The sophisticated and complicated PTC technology must account for a number of factors to measure the appropriate train stopping distance, including train information (weight, length); track composition (curvature, terrain); train speed and train authority (authorization to move across a stretch of track).​​​

There are three main elements of a PTC system, which are integrated by a wireless communications system:

1. Onboard or Locomotive System
Monitors the train’s position and speed and activates braking as necessary to enforce speed restrictions and unauthorized train movement into new sections of track.

2. Wayside System
Monitors railroad track signals, switches and track circuits to communicate authorization for movement to the locomotive.

3. Back Office Server
The storehouse for all information related to the rail network and trains operating across it—speed limits, track composition, speed of individual locomotives, train composition, etc.—and transmits the authorization for individual trains to move into new segments​ of track.


Developing PTC Technology
Much of the technology PTC requires did not exist when the mandate became law in 2008. Railroads had to develop the required technology for locomotives, wayside interface units and back office systems from scratch. Once developed, each element must undergo rigorous testing before it can be deployed. Railroads have also been challenged by the limited number of firms that provide technology design services, particularly for signal systems, many of which have to be redesigned before PTC technology can be installed.

Deploying hundreds of thousands of technology pieces
PTC involves the deployment of hundreds of thousands of technology pieces—from onboard locomotive systems to switch position monitors—across the nationwide rail network.

Geo-mapping 60,000 miles
The approximately 60,000 miles of railroad right-of-way on which PTC technology will be installed and nearly 440,000 field assets (i.e. mileposts, curves, grade crossings, switches, signals, etc.) must be precisely geo-mapped for PTC technology to work correctly. This mapping forms the basis for the system’s track database used by the back office server.

Interoperability is essential
To function properly, PTC systems must be interoperable so that any train operating on another railroad’s network can communicate with the host railroad’s PTC system. 

Equipping approximately 3,300 “dark territory” switches with power
Some long stretches of track in remote areas use only one main line without any signalization. To make these areas PTC compatible, railroad switches must be upgraded and electrical power must be brought to the site.

Phased rollout is critical for safety
Implementation of PTC must occur in phases and location by location, starting with less complex areas and proceeding to the more operationally complex areas with lessons learned incorporated at each step to ensure that the system functions safely. Rushing PTC development and installation and foregoing a logical plan for sequencing its implementation would sharply increase the likelihood that the system would not work as it should.

Required testing software is not available
Once all testing of individual PTC components is complete and those components have been installed, testing of the entire system as a whole can begin.

220 MHz network is still under development
To support interoperability, the rail industry is adopting the use of 220 MHz radio channels as a common means of wireless data communication. Specific allocation of channels for PTC has not occurred and railroads have had a difficult time acquiring the necessary amount of spectrum on the open market, particularly in metropolitan areas.

Training cannot be completed until the PTC system is operational
PTC requires rigorous training for 114,515 Class I railroad employees—more than 50 percent of the rail workforce—and although training has begun, it cannot be completed until the system is operational.


America's freight rail industry has been—​and remains—committed to fully implementing PTC across America's freight rail network as quickly, safely and responsibly as possible. In fact, the rail industry's PTC progress to date has been substantial since enactment of the Rail Safety Improvement Act of 2008 (RSIA). Railroads have devoted enormous human and financial resources to developing a safe and fully functioning PTC system.

To date, railroads have retained more than 2,400 signal system personnel to implement PTC and have already spent more than $7.1 billion on PTC development and deployment. They have developed new technologies from scratch and made considerable progress overcoming some of the biggest challenges associated with PTC, including geo-mapping nearly 60,000 miles of track to enable GPS guidance.

In the years to come, freight railroads will continue to safely deploy all necessary equipment and outfit the locomotive fleet with PTC technology. The rail industry will also conduct thorough testing and validation to ensure that the system works, before this groundbreaking and technologically complex system is operationalized across the freight rail network.