What is PTC?
Positive Train Control (PTC) is a GPS-based safety technology system that monitors a train’s movements in real-time and will stop a train to prevent train-to-train collisions, over-speed derailments, and unauthorized train movements through work zones or any other restricted section of track. Federal law required that every freight and passenger railroad operating in the U.S. install and operate with PTC by of Dec. 31, 2020. All commuter and freight trains across the Chicago region are now operating with PTC, and it is being cited in our service alerts as a cause of some delays. To view a more detailed explanation of how PTC works, click here.
How can PTC delay a train?
In general there are four types of issues that could cause a PTC delay. They are: software, hardware, wayside communications and human error.
Software issues have been a common cause of Metra’s PTC-related delays. The software that runs PTC is extremely complex and must be adapted to every unique aspect of our railroad. Metra continues to work with the PTC software developer to fine-tune the system's software and adapt it to Metra's operating environment to reduce these types of delays.
Hardware issues are the result of the failure of one of the numerous components of the PTC onboard computer system.
The wayside communications system monitors railroad track signals, switches, and track circuits and communicates the alignments or indications of track equipment to the onboard system to allow a train to move through a section of track. A failure at any stage in this communication link will stop a train because the PTC system is not receiving data.
Human error issues have also been a common cause of Metra’s PTC-related delays. This type of error has occurred across the rail industry as PTC has been implemented, but the number of human errors have been shown to decline quickly as users gain experience and familiarity with the system. Human error issues can range from mistyping data during the train’s initialization process to the engineer disregarding or not responding quickly enough the PTC system’s instructions. In the second example, the PTC system is functioning as designed when it stops the train.
A PTC issue sometimes requires that the engineer reset the onboard equipment, a process that can require about 10 minutes to complete. PTC also requires the engineer to perform an initialization prior to each train run. These requirements are the primary reason that we’ve modified schedules across the Metra system to provide extra time between equipment runs and accommodate PTC initialization.
As PTC technology matures on the Metra system and Metra's and its freight partners' familarity with PTC operations increase, we expect the number of delays attributed to PTC to steadily decline.