It stretches from the Harrisburg Line at Wyomissing Junction in Wyomissing, Pennsylvania to a junction with the Lehigh Line in Bethlehem, Pennsylvania.

The line opened as the East Pennsylvania Railroad on May 11, 1859, connecting Allentown with Reading.

In 1976, The Reading Railroad was acquired by Conrail, which continued to use the line as a conduit between North Jersey and the rest of the country.

When Conrail was split in 1999, Norfolk Southern was assigned the line.

The speed change was intended to increase the efficiency of rail operations and improve the flow of vehicular traffic at grade crossings.