The following information was prvided by Bob Schmidt who lived at the top of the Harwood Street steps that led up to South Hills High School.
The right o' way from the Junction to Warrington Ave. was special since I could survey this view from my second story bedroom window. The family and neighhbors called this area "the hollow". There was a loop that made its way starting 50 yds. East of the junction and running off to the right, and parallel to, the right o' way trackage used for the 44/48/49 routes that went East onto Warrington. The track looped under the girder bridge and came around to the base of the Harwood Stop steps. The loop was used for the County Fair cars in early September as a launch point to downtown for passenger pickup direct to the South Park Fairgrounds. To the best of recollection the "loop" was used for this service from 1940-1952. One would always know the Fair wasn't far off when the PRC laborers cleared the rusty tracks of the loop with their long handled scythes about July 15th followed by the weed spraying car, and a 4300 car converted to a rail grinder to 'polish' the rails that had lay dormant for nearly 11 months.
The red/gray Charleroi 3800, Little Washington 3700 interurban cars, and a foray of orange 4300 series cars would line the loop trackage at around 8:00 PM and depart 7:00AM the following morning at 10-minute intervals. A highlight of my boyhood days was a ride on a 3800 car to Charleroi in one of those swiveling bucket seats with my Mom when I was 6 years old.
I used to loiter around the Administration building simply to be around the trolley action..especially every Friday at 4 PM when M-1, the Pay Car, would pull onto the diagonal track at the rear of the junction building having come down the hollow from Warrington Ave. to mete out the conductors pay checks. It was a dark brown, wood-sided, car with wire mesh over all side windows, and with a four-wheel central truck which made the car rock up and down. I fondly called M-1 "the dinky". M-1 ended up at Arden, PA where it was stashed beneath a canvas tarp for eventual rebuilding. I don't know what the disposition of this particular car is at this time. It may have been too far gone to resurrect.
From what I can remember, the Junction Building had a dank void smell... mostly of stale cigarettes which the motormen would smoke like a chimney between their scheduled runs. They would always chase me as discussions were relative to 'men talk' and little guys weren't supposed to be listening to that banter.