This short spur line branched from the Wilmington and Northern's line at Elverson, and headed east to serve a black granite quarry at Saint Peters. The line passed through the small town of Warwick, which gave this branch line its name. The line once connected with the end of The Delaware River and Lancaster Railroad at Saint Peter's via a switchback.
Date of abandonment is not known; it appears on a 1948 railroad map under the Reading Railroad.