A bit of background. Boyce Park is situated on land donated by the State of Pa and was the site of Mayview State [Mental] Hospital. The park is bounded on one side by Chartiers Creek. The Pittsburgh and Ohio Central Railroad follows the creek for several miles so walking in the park often provides an opportunity to see the morning switching-job roll down the creek. This was the Chartiers Branch of the PRR:
https://en.wikipedia.org/wiki/Chartiers_Branch
Carsten Lundsten has an excellent webpage with photos and a map of the P&OC:
http://www.lundsten.dk/railfan_pa/poc/index.html