"爸爸经常坐火车" 的英文表达可以是 "Dad frequently takes the train."。

这句话的来源是英语中 "爸爸" 对应的是 "dad","经常" 对应的是 "frequently","坐" 对应的是 "takes","火车" 对应的是 "the train"。

一些英文例句和中文翻译:

"I often see Dad at the train station." (我经常在火车站看到爸爸。)
"Dad always takes the 6:00 am train to work." (爸爸总是乘坐早上6点的火车去上班。)
"Is Dad on the train now?" (爸爸现在在火车上吗?)