Overview
Background
On multiple-unit (MU) trains, trains composed of several carriages joined together, communication is sent between coaches across trainlines, wires that run inside of coaches. The trainline controls all of the key functions of the train, including the doors, lights, and sounds. On the MBTA Commuter Rail, the trainlines also control traction interlock (TI), an important safety feature that ensures all doors are closed before allowing power to be sent to the train. However, TI is a faulty system, resulting in almost 300 trains delayed and over 25,000 passenger journeys affected since being implemented on May 24, 2021 until July 16, 2021.
The testing process for trainlines is extremely time intensive, involving two trained technicians individually probing 216 pins. As a result, trainline issues are one of the main causes of delay on the Commuter Rail. The goal of my project was to improve fault-finding for trainline issues, including TI, by automating the process with a wireless Raspberry Pi device controlled with Python. My device checks for both continuity and crosswires (that signal was received at only the correct pin), as well as enables input/output testing (pressing a button on an iPad tests specific functionality, such as opening doors).
Concept
Prototyping
#1 End
#2 End
Controller
*turn on audio* to hear relay clicks
Note: Videos are not synced together
Prototype successfully sent signal across trainline with results accessible from iPad
Back of train
Front of train
The next steps to transform this prototype into a deployable product include replacing much of the wiring with PCBs, fully integrating a graphic user interface (GUI), and gaining buy-in from the technicians who do trainline testing and the company at large.