This tower is a one of a kind single story brick building, containing a 39-lever Union Switch & Signal Model P interlocking machine. In its heyday, PARK interlocking was a 4-track full crossover and was the junction with the Pennsylvania Railroad's main line with its Atglen & Susquehanna low-grade freight bypass. In later years, atrophy began to take its toll. In the late 1970s, the Atglen & Susquehanna branch was reduced to a single track and in 1990 it was completely abandoned and removed. Amtrak later removed the two center tracks (track 2 & 3) between here and CALN interlocking to the east, making PARK interlocking nearly irrelevant except for a local industrial track that used the otherwise-abandoned A&S right-of-way; because of this arrangement, PARK tower was only open on an as-needed basis.PARK interlocking was a 4-track full crossover and was the junction with the Pennsylvania Railroad's main line with its Atglen & Susquehanna low-grade freight bypass. In later years, atrophy began to take its toll. In the late 1970s, the Atglen & Susquehanna branch was reduced to a single track and in 1990 it was completely abandoned and removed. Amtrak later removed the two center tracks (track 2 & 3) between here and CALN interlocking to the east, making PARK interlocking nearly irrelevant except for a local industrial track that used the otherwise-abandoned A&S right-of-way; because of this arrangement, PARK tower was only open on an as-needed basis.