Massachusetts Bay Transportation Authority

Quester Tangent implemented a tailored Train Monitoring System that provides easy access to a complete operational overview of the entire fleet, supported by data networks integration for enhanced compatibility between new and legacy vehicles.

Project overview

Project name: Bi-level commuter coaches

Client: Hyundai-Rotem

Type of project: New

Vehicle application: Commuter rail

Number of vehicles: 75

No. of QT units sold:

  • 75 Monitoring and Control Units (MCU)
  • 75 Train Network Controllers (TNC)
  • 28 Operator Display Screens (ODS)
  • 56 Exterior Light Controllers (ELC)
  • 56 Windshield Wiper Power Supplies (WWPS)

Contract awarded: 2009

In-service date: 2015


  • Train Control and Monitoring System

Location: Boston, MA

Providing a complete overview of train composition and real-time operational status

In 2009, Quester Tangent was contracted to supply a Train Monitoring System (TMS) to the Massachusetts Bay Transportation Authority (MBTA) for its new bi-level commuter coaches.

There were 28 Control Trailer Coaches (CTC) and 47 Blind Trailer Coaches (BTC), for a total of 75 coaches. All coaches were supplied with Monitoring and Control Units (MCU) and Train Network Controllers (TNC). The CTCs were also supplied with Operator Display Screens (ODS), Exterior Light Controllers (ELC), and Windshield Wiper Power Supplies (WWPS).

Fast, easy access to real-time and archived train data

The new Monitoring and Control Units perform the main processing, communications, fault monitoring, and data-collection functions for the Train Monitoring System. The MCU obtains status information from vehicle subsystems via the car network, analog signals, and discrete trainlines, logging real-time status and fault data in support of operations and maintenance. The TMS allows communication between the MCUs installed in each coach over the train network.

In a Control Trailer Coach, the Monitoring and Control Unit is connected to an Operator Display Screen that shows operational and maintenance information on a rugged touchscreen display. Train crew have easy access to real-time conditions and troubleshooting tools for fault conditions in the CTC. In addition, the ODS provides a complete overview of the current train composition, doors, and fault status for all TNC-equipped cars in the consist.

Data networks for enhanced fleet compatibility

Quester Tangent implemented a digital train network over existing trainlines using power line communication technology between vehicles. The supplied Train Network Controller coordinates with the TNCs in other cars to create a list of all cars connected to the network, including car number, car orientation, and car order within the consist. This information is displayed to the operator on the ODS in a visual representation of the consist. The TNC manages the train data network and performs the store-and-forward exchange of all data between the MCUs on every car.

Because the Train Network Controller uses existing trainlines, the power line data network continues to operate even if legacy cars without a TNC are included in the consist.

This data communication network allows MBTA to save on added wiring costs and to exchange critical operational data between cars and locomotive while maintaining trainline compatibility with its older fleets.

Power regulation for added reliability

Powered from the Low Voltage Power Supply (LVPS) system, the Exterior Light Controller provides regulated power to drive the headlights and other exterior lights, and the Windshield Wiper Power Supply provides regulated power to drive the windshield wipers in the Control Trailer Coaches.

With this project, Quester Tangent demonstrated the flexibility of its products and its rail transit expertise by developing cost-effective, highly reliable solutions that met the unique requirements of MBTA and Hyundai Rotem.