MTA Subway Mean Distance Between Failures: Beginning 2015

Mean Distance Between Failures reports how frequently train mechanical problems cause delays by month and subway car class. It is the main indicator for subway car reliability used at NYCT and is used to compare performance over time and across different subway car types. Only a small proportion of subway delays are due to malfunctioning trains.

平均故障距离（Mean Distance Between Failures）用以衡量因列车机械故障导致延误的频率，按月份及地铁车辆类别进行统计。该指标为纽约大都会交通局（NYCT）评估地铁车辆可靠性的主要依据，并用于对比不同地铁车辆类型随时间的变化性能。仅有极小比例的地铁延误是由列车故障引起的。