vehicle id's?

[Nicholas Johnson]

So I am tracking a couple trips - 119 & 121 - and it seems like the vehicles are starting fresh with each trip. While the vehicles for other trips use vehicles that have been on other trips, the vehicle ids for 119 & 121 seem to only appear at the beginning of their trips.

Is this normal?

[Developer at MBTA]

Hi Nicholas, 

Yes, that's normal. Equipment is carefully cycled in and out of service each day so it can be fueled and maintained when it's not in service. So some trips typically involve a new set of equipment coming from the railyard, and it's not even unusual for that to be concurrent with other equipment returning to the railyard so equipment can spend part of the day in service and part of the day being cleaned, fueled and maintained. 

Sincerely,

developer@mbta