the tracks
n. The line between the rich or fashionable part of town and the poor or unfashionable part of town.
The poor children knew they would not be welcome on the other side of the tracks.
Mary's mother did not want her to date Jack, because he came from across the tracks.
■ Often used in the expression "the wrong side of the tracks".
The mayor was born on the wrong side of the tracks, but he worked hard and became successful.

[TahlilGaran] English Idioms Dictionary ▲