A history of the line is found in Thomas T. Taber's publication "Susquehanna, Bloomsburg and Berwick Railroad - A History".
Under Conrail this former PRR branch line ran 39 miles from Watsontown to Berwick, PA, entering the former ACF Berwick complex from the west end. At this time the former ACF complex was owned by Berwick Industrial Development Association (BIDA) and Berwick Forge and Fabricating Corp. (BFF) was a tenant producing boxcars. Due to a clearance restriction on the former EL Bloomsburg Branch, which accessed the complex from the east end through a stiff grade and street running, new high clearance boxcars were shipped out the Watsontown-Berwick Secondary. By the spring of 1978 the clearance restriction on the Bloomsburg Branch with the former Reading Catawissa Branch at Rupert had been raised. That ended service through to Berwick on the Watsontown-Berwick Secondary.
The west end of the line was very busy with unit coal trains to PP&L's Montour Steam Electric Station at Strawberry Ridge (RIDGE- MP 11.5), and beyond RIDGE there was limited fly ash and fertilizer business. By late 1982 the track east of MP 14 was dismantled. The track from Watsontown to RIDGE became the Watsontown Secondary and the track from Ridge to End of Track became the Watsontown Industrial Track.