The eight Massachusetts Bay Transportation Authority trains that derailed last year were the most of any light rail public transit agency in the country.
The federal National Transit Database, which tracks safety data for transportation systems, says six Green Line trolleys and two subway maintenance vehicles derailed in 2016.
The New Orleans Regional Transit Authority and the San Francisco Municipal Railway each had six derailments.
No injuries were reported in the MBTA's derailments, which sometimes involved out-of-service trains or overnight maintenance vehicles. None involved a collision.
Jeffrey Gonneville, the MBTA's chief operating officer, tells The Boston Globe that the T is safe and the agency has a team that regularly checks and maintains tracks.
Commuter rail is not included in the statistics.