Warning
I’m not a signal engineer. This is all armchair analysis from someone who has more experience with rapid transit—but even then, I’m not an engineer! I work on transit performance data from an office. Talk to your local signal engineer for advice. With this project I seek only to learn more about mainline PTC, and hopefully contribute to public knowledge while doing so.
A little more than a year ago, Caltrain finally launched electric service between San Francisco and San Jose after decades of planning, construction, and procurement. The project has been incredibly successful, dramatically increasing ridership, cutting travel times, and preparing for California High Speed Rail to enter San Francisco (a project which, despite the claims of detractors, is happening). Though parts of the process were painful, for riders and for Caltrain, the prevailing sentiment has been that it was all worth it. In the year and change since, little attention has been paid to what I think is the most interesting part of the project: Caltrain’s aborted attempt at a custom PTC system.
On the 11 of February, I submitted a public records request to the Peninsula Joint Powers Board (JPBX, or Caltrain) under the California Public Records Act, seeking information related to the architecture, design, and technical workings of the doomed Advanced Signal System Project, or CBOSS, which was an attempt to create its own FRA complaint PTC system.
Others have written many words about CBOSS.1 Much has already been covered. I seek only to look in to the technical nature of the project. Very little is publicly known about how CBOSS would have worked, how it would have interfaced with California High Speed Rail’s own PTC and signal systems, and what it would have looked like in operation. I seek not to make accusations relating to the District’s handling of the project,2 but just to explore the design of a system that never was.
CBOSS never made it to use. Before the project’s completion, the District terminated their contract with Parsons, who was building CBOSS, citing non-performance. Wabtec was brought on to replace CBOSS with the widely-deployed I-ETMS (Interoperable Electronic Train Management System). PTC deployment, especially in the Western parts of the country, has been fraught with issues. CBOSS was no exception. As railroads outside of the northeast have largely fallen into line and all deployed I-ETMS or similar, CBOSS offers a look at what the PTC landscape could have looked like.