With one possible exception, I can say with near-certainty that there were no interlocking plants on the "Bloom" south of Plymouth Junction at any time. The line was double-tracked from Scranton south to West Nanticoke, and I'm fairly sure the switch at the EDT (end of double track) was hand operated. though the junction with the D&H wouldn't have been too far north. The Lackawanna maintained an Absolute Permissive Block signal system, using lower-quadrant semaphores, until some time int the early 1960's, and the end of passenger service in the spring of 1953 left no conflicts between the Monday-Friday Kingston-Danville Local and the nightly Taylor-Rupert-Northumberland through freight.
The Lackawanna's interchange with the Reading at Rupert, about two miles south of Bloomsburg, did not involve a crossing at grade, so no interlocking was needed. The Reading and PRR did cross at grade at NORCA on the other side of the Rupert-Catawissa bidge. and a second interlocking involving the Reading and PRR's Catawissa-Rock Glen line, and designated REDPEN, endured until about 1949 at the south end of town, though it was used only on an emergency basis for rare interchange moves after the line was cut back in the late 1930's.
The "Bloom" turned westward to enter the PRR's Northumberland yards, and to my knowledge, no wye was ever built to allow Lackawanna trains to access Pennsy's Sunbury station without a reverse move, though some timetables do indicate a direct connection at Sunbury. Early photos of Northumberland do show a tower at the east/south end of the yard, designated as Tower N, but I've not yet found an Employees' Timetable to document the rules of the day. It's a pretty good bet, however, that that tower did include an interlocked switch to the "Bloom" at one time.
I'm also not sure what arrangements were in place for the junction with the Hanover and Newport Branch, which crossed the Susquehanna to serve four breakers to the south and east of the City of Nanticoke, and was plenty busy until anthracite traffic statrted falling off in the wake of the 1925 strike. Lackawanna used to maintain a yard for empties between Kingston and Plymouth, but it disappeared not long after the Knox mine disaster.
North of Plymouth, the "Bloom" crossed the Lehigh Valley's main line from the large yard at Coxton (across the Susquahanna from Pittston) to downtown Wilkes-Barre, but most LV freight traffic used the Mountain Cutoff from Coxton to Mountaintop (Gracedale Tower) via Dupont. The tower at Coxton was designated PITTSTON JCT, and survived as a manned interlocking until probably some time in the 1980's
Finally, There were likely at least one, and possibley two or three interlockings in the Scranton area. The "Bloom" served the freight yards at Taylor, which survive to this day under joint CP/NS operatiion. From Taylor, traffic could move either east to the Scranton passenger station and freight yard/LCL hub. or further north via the Keyser Valley Branch to a junction with the Main Line at a tower designated CAYUGA. The DL&W's Keyser Valley car shops and a large classification point for coal traffic (Hampton) were located on ths line.
By the time I arrived on the scene, all the DL&W's Scranton area operations, Taylor included, were consolidated into a single US&S CTC-type panel at the BRIDGE 60 Tower (now the Steamtown NPS Police HQ) at the west end of Scranton Yard. That machine replaced the towers at EAST END(near the U of Scranton campus). MATTES STREET (standing, but vacant, across from the Lackawanna Station hotel), the first BRIDGE 60 (origins, structural details and configuration unknown), DIAMOND CROSSING (CNJ, LV and NYO&W interchanges), CAYUGA, and whatever previously existed at Taylor.
What a revoltin' development this is! (William Bendix)
