In March 1882, the PRR completed the four tracking of the line between Houtenville and South Elizabeth with the completion of a four-track bridge over the Rahway River in Rahway. On April 1, 1882, Uniontown station was renamed Iselin. On November 5, 1882, the new PX interlocking tower was placed into service at Perth Amboy Junction in Rahway. In 1885, with the exception of through the cities of Trenton, New Brunswick, Elizabeth, and Newark, the line was completely four tracked between Trenton and Jersey City.