The historical society Slugger mentioned is for Brookville, OH not PA.
Very little rail activity remains in Brookville, PA to date, currently the Buffalo & Pittsburgh owns the former PRR line coming into town and connecting to the Pittsburg & Shawmut where Brookville Equipment is located. This track is out of service for inspection purposes as it sees very few movements annually to Brookville Equipment, the only customer on the line west of DuBois. If you are looking for active rail action, I recommend heading east 20 miles to DuBois-its not extremely busy, but during the week you are guaranteed at least 4 trains a day.
The former PRR west of Brookville is part of the beautiful Red Bank Valley Rail Trail: https://www.redbankvalleytrails.org/ Just east of where the trail joins the former PRR, the line went through a tunnel and immediately across Sandy Lick Creek. The former PRR freight station is located here off of Western Ave. The large P&S trestle is east of here and can be seen crossing over Lincoln St. Be mindful of your traffic signs, the streets can be both steep, narrow, and most are one-way only.
