inferior train

例句：

1. 1. The substandard train was late and caused a lot of inconvenience for the passengers.
   这辆劣等火车晚点了，给乘客带来了很多不便。
2. 2.The company decided to upgrade its substandard trains to improve service quality.
   公司决定升级其劣等火车，以提高服务质量。
3. 3. Due to the poor maintenance of the substandard train, it had to be retired earlier than expected.
   由于劣等火车维护不善，不得不提前退役。