I grew up in Tamaqua and lived close to the LNE. There really was no double track per se, but the appearance of it through the eastern section of town towards Arlington. The track from Pen Argyl turned east from following Rt 309 and was joined by the track that was used for Reading RR interchange, as well as a couple house and team tracks that existed between Greenwood Av and Hazle St crossing and Broad St crossing. The Pen Argyl turns operated specifically on the one track, and the interchange local job operated specifically on the other, between the years of 1956 to 1961.
Just past the Broad St crossing [which had 3 tracks due to a siding] the right of way split into 4 tracks, with a siding off each of the previous 2 tracks I mentioned. Of interest in that location was a spring switch with a red/green indicator. The lone RS2 would come west to that point and cut off the outgoing consist for the PAT, usually a hundred or so loaded hoppers around 2p. As soon as uncoupling they would attach an air hose connected to a long pipe which ran along the right of way to keep the train charged.
The inbound PAT, mostly 4 FA's would roll through between 4p and 430p with the empties. They would cut off the train in Arlington Yard and run back light to the siding [on that single track main] and couple to their train, removing the standing air connection and replacing it with the engine consist air. More often than not they would roll by 5p-515p in a whirl of Alco Smoke. By the time the caboose went by they were really going fast. I use to watch and wait for the spring switch, now indicating red, to flip back and indicate green.
The LNE was frugal but kept well maintained track and in most places did 50 mph. An interesting operational move they did, as an example of their frugality, was to deadhead the RS2's they exchanged for those due their 92 day inspection, on the rear of the train ahead of the caboose. It was a few years until I was old enough to be able to go Arlington and observe why this was done. When the PAT stopped in Arlington yard, the RS2 now due its 92 day inspection was coupled to the rear of the arriving empty train. The crew then pulled off the caboose and inspected RS2 and coupled that [RS2 - caboose - RS2] to the outgoing loaded coal train. They climbed off the RS2 due inspection, walked back to the newly inspected one and uncoupled from the caboose, all in a very quick move. The RS2 crew then went about their local mine business with their new RS2, while the FA's quickly uncoupled form their empty consist and ran back to their loaded consist to get out of town.