The March 1959 Official Guide shows the following (in each direction, Mon-Fri except as shown):
Derry -- 4, incl. 1 Sat., plus 4 to North Trafford, plus 1 eastbound to Braddock, no wb counterpart (one of the Derrys was nonstop Irwin to E. LIberty in the am, E. Lib. to Larimer in the pm) Included in the North Traffords were 2 wb in the am and 1 eb in the pm.
Kiskiminetas Jct. via Allegheny Valley -- 1
Kiski Jct. via Conemaugh -- 1
Beaver Falls -- 2, incl. 1 Sat
Burgettstown -- 2, incl. 1 Sat
Elrama -- 1
I lived in Pgh. in 1962, and that was all still running then, except perhaps some of the North Traffords.