The branch included a 1,200-foot tunnel at Grimms Bridge, and a trestle over Beeler's Run.
Operation of the Smiths Ferry Branch began in mid-1936 with 50 to 60 carloads daily. Coal mined from Pittsburgh Coal along the Monongahela River was shipped by barge to Smiths Ferry where derrick shovels transferred it into a waiting train. The coal was then hauled a plant south of Negley where it was washed, graded and reloaded. It was then taken to Negley and transferred to the Pittsburgh, Lisbon & Western Railroad. The coal was hauled seven miles to Signal where it was taken over by the Youngstown & Suburban and delivered to steel mills in and around Youngstown.
In 1967, the Tassi Coal Company, a strip mine operation, went bankrupt. The mining in the Grimms Bridge area included work on a hill above the Grimms Bridge tunnel. After a heavy rain, spill and rock slid over the edge of the hill and covered the south end of the tunnel.
Without the funds to clean up the tunnel, the Y&S sought federal permission to abandon the Negley-Smiths Ferry Branch on April 26, 1977.