Positive Train Control (PTC)

 What is Positive Train Control?

Positive Train Control (PTC) is a federally mandated system to monitor and control train movements that will help prevent train-to-train collisions, speed-related derailments and incursions into zones where work may be taking place. The current deadline for compliance is December 31, 2018.

Installation work will be performed on every Commuter Rail line, dispatch center, locomotive, and control car, impacting operations system-wide.


How does it work?

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.
  1. Wayside System: Monitors railroad track signals, switches and track circuits to communicate authorization for movement to the locomotive.
  1. 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.

How will service be impacted by installation?

Weekend shutdowns will be necessary to complete the installation of PTC. The MBTA plans to have no more than two lines experience weekend service suspensions at a time. Work that does not interfere with train traffic has already been on-going along most Commuter Rail Lines.


Why do different lines have different project timelines?

Each line of the Commuter Rail system has different lengths, features and levels of infrastructure already in place which affect the amount of time work needed to be performed. Nevertheless, project managers are already working to do as much work in advance of any shutdowns, mitigating disruptions. (E.g. PTC installation on the Newburyport/Rockport Line has been scheduled to coincide with the outage of the Beverly Swing Bridge over the Danvers River. This coordination means the PTC installation will only require 13 weeks of work compared to 27 weekends of outages.)


Why does the whole line need to be shut down?

  • Safety is increased – The risk to those working on the right of way is dramatically reduced when trains are not running. Additionally, more work can be performed during daylight hours.
  • Accelerated project timeline – One complete weekend shutdown per line can accomplish what would require two weeks of weekday off-peak (night) work. When work can take place during days and nights, the opportunity to complete the project on-time is greatly maximized
  • Less of an impact on commuters – 90% of our customers are weekday commuters.
  • Successfully implemented on recent projects – Similar weekend service suspensions have been positively utilized on Old Colony and Fitchburg Projects in recent years.


What will PTC cost?

With 80 per cent of funding coming from federal loans and grants, the remaining 20 per cent will be provided by the MBTA. The total program cost is approximately $459 million.