 The combined railroads were sometimes unofficially referred to as the Auburn and Allentown Railroad.On April 13, 1854, the charters of both the Allentown and the A&PC railroads were amended to allow them to merge with the Lehigh Valley Railroad, then building down through Allentown towards Easton (across the river from Phillipsburg).The line from Pine Grove to Rausch Gap was completed in June, and the D&S ran its first through train.