APIv2 heavy rail vehicle_id issue?

[StefanW]

I'm seeing an issue with the vehicle_id on all heavy rail subway lines (Red, Blue, Orange) in APIv2, The values are things like 544598E6, 54459F2F, 54459F2F. 

Can anyone confirm this?

[Developer at MBTA]

Hi Stefan,

We made a change last week to improve the new performance-related API calls. This change resulted in our vehicle IDs no longer being simply the lead car number, but rather a unique identifier for a particular train. In addition to helping our system track trains more accurately for performance purposes, this brings the API closer in line with the GTFS-realtime specification, which suggests that a vehicle's id should be a unique identifier that does not change over time (the lead car number changes every time a vehicle reverses direction, making it inappropriate for use as an identifier).

We apologize for making this change without properly informing developers first, and we understand that you were relying on vehicle ids to match lead car numbers. Since there is utility in knowing the lead car number of a particular train, we hope to soon add a "label" field in the API which, similarly to the "label" field in the GTFS-realtime specification, will be a human-readable label for the vehicle, which will be the lead car number in the case of our rapid transit services.

Note that this label/id distinction is already in production for the GTFS-realtime feed; the change we hope to make in the API soon will bring the API call in line with the GTFS-realtime format.

Sincerely,

Developer@MBTA

[StefanW]

OK, I'll sit tight until you can add that label to the API. I hope the vehicle_id won't change for Commuter Rail in the API until after you've added the new label and allowed some time for us to make app updates.

Needless to say, please feel free to involve me / us in pre-production testing of data with the label field!

-- Stefan

[Developer at MBTA]

We won't be making any changes to Commuter Rail at this time (or Green Line, as this currently only affects Red/Orange/Blue). In the future we'll make sure to inform the developer community in advance of any such changes. And thanks as always for your close attention to our data feeds.

Sincerely,

Developer@MBTA

[Konos]

Hello,

I received few emails from my users complaining about that change in vehicle ID. Some of them are MBTA inspectors and they said that my app (with previous vehicle ID info) was helping them in their job. When do you expect to have it (vehicle label field) available in real-time data feed?

Thanks,

Andrzej

On Thursday, May 5, 2016 at 4:04:09 PM UTC-4, Developer at MBTA wrote:

[StefanW]

It's been three months since I first wrote about the vehicle_id for heavy rail. Please (MBTA folks) give us an estimate of when we can see actual vehicle ID numbers back in the feed.

In addition to the use case cited by Konos on May 24, I'll illustrate a specific use of my app which has been broken for three months...

When a train arrives at a station, a rider used to be able to look at the car number on the leading vehicle as it passes, then find that vehicle in my app, and find out when that train / trip would arrive at a station later down the line. This makes planning for connections much easier. For example if you have a choice of Bus or Commuter Rail for a later part of your trip, it becomes important to know when you will arrive at the connecting station. Without the actual vehicle ID that becomes impractical. 

I'm thrilled that you are working on getting the departures / track assignments into the standard feeds, but I'm disappointed that it seems like you're working on those new features without first bringing back data that we used to have... especially since the true heavy rail vehicle ID was removed without any advance notice.

Thanks for your consideration.

-- Stefan