The railroad had a lot to do, too, of course, with linking northeast with northwest, which has a lot to do with a certain sense of economic isolation that set in in the South, to some extent.

铁路也连接了,美国东北和西北地区,在一定程度上,它和当时南方,某种意义上的经济孤立脱不了干系

耶鲁公开课 - 美国内战与重建课程节选