gravy train 赚大钱的清闲差事、美差、肥缺

Gravy train: A job that pays a lot of money for very little effort 赚大钱的清闲差事、美差、肥缺

例：

Ian earns a fortune for three hours' work a day. He's really on the gravy train!

伊恩每天只用工作三小时，薪水却很高，他真是得了一份美差！