Updates to real-time Commuter Rail trip information

[Developer at MBTA]

Dear developers, 

Today, we made a small change in our real-time architecture that affects how we publish data for Commuter Rail trips that have yet to depart a terminal. We made this change to improve the simplicity and resiliency of our architecture. However, app developers may need to adapt, especially those aiming to replicate the “big board” departure boards at North and South Stations. 

Before today, Commuter Rail trips that had not yet left their origin (e.g. trains waiting to depart at North or South Station) would generate a "live" prediction in TripUpdates and were automatically designated with an ON TIME status. 

Now, a live TripUpdate won’t be published until a boarding status (e.g. 'Boarding', 'All Aboard', 'Delayed', etc.) is posted for the trip, or a prediction update is available. Essentially, we won’t offer “live” trip information until we have it. 

Developers emulating the “big boards” or wishing to display upcoming departures at any station should display all upcoming scheduled and predicted departures, even if no TripUpdate is present. If desired, apps can assume a trip will operate as scheduled until there’s a live boarding status or updated trip prediction. 

As always, please let us know if you have any questions. 

Thanks,  

Developer @ MBTA