Commuter Rail location data improved

[Developer at MBTA]

If you use our commuter rail real-time vehicle locations, you may have noticed something strange today: our commuter rail trains got faster.  

No, we didn’t just buy new locomotives. But we did make a back-end change to improve the latency, frequency, availability, and reliability of our commuter rail train location data. Keolis developed a new interface into their train tracking system, and the MBTA worked with them to tap into it and provide the locations to Swiftly, who we work with to turn current locations into arrival predictions. Swiftly switched to this new feed today.

Previously when requesting the location of a commuter rail train, the timestamp would show that this was a location reported around 2 minutes ago, or even longer; the location would be updated once a minute, at most. Now when requesting a commuter rail train location the location should be no more than 35-40 seconds old, and maybe more recent than that. It is normally updated every 30 seconds. And with newer data and more data points, arrival predictions will be more accurate too.

We expect commuter rail data to be more reliable and more consistently available now. One side effect at this stage is that there can be a delay in the time it takes a train that’s completed one trip to be assigned to the next trip it will operate; we’re working on this issue.

We hope this benefits you and your users. Please let us know if you notice any other issues with commuter rail data.

Sincerely,

developer@mbta

[Michael Barry]

This looks great! We notice a big improvement in timeliness and resolution of historic data on https://mbtatrains.com

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[Eric]

One of my users pointed out that Commuter Rail train speeds have been uncharacteristically low since this change was deployed. I've been keeping an eye on it tonight and haven't seen a train go past 27mph. Granted I've only been paying attention for a couple hours, but do you think this change could have altered how speeds are reported?

[Stefan Wuensch]

I noticed the same thing just recently and I was initially thinking it is a meters-per-second vs. miles-per-hour switch. I’ve only tried a few manual conversions, but dividing the value we’re seeing now by .447 appears to get a value that’s believable as MPH.
(1 MPH == 0.447 M/s)

Sent from my iPad Micro

[Developer at MBTA]

We did some double-checking and we believe we're publishing the correct speeds in meters per second. Speeds in V2, V3, and GTFS-realtime should be in meters per second. If the values we were publishing in those channels before were actually mph, then that was a bug we weren't aware of.

Sincerely,
developer@mbta

[Stefan Wuensch]

It may be a non-issue now - meaning, fixed / resolved. Over the weekend I also saw no train get above 27 or 28 (what I thought was MPH) but today there's been lots that are reporting 60+ MPH. I'll keep watching but there seems to be no problem currently.