to WATCO, the current operator the segment from Toledo to Osmer. The Pennsylvania years The line operated as an independent subsidiary of the Pennsylvania Railroad from 1929 until 1970. In 1955, the line replaced its steam locomotives with diesel locomotives. The DT&I relied exclusively on diesel locomotives built by General Motors Electro-Motive Division. The later years In 1968, the DT&I's parent company, the Pennsylvania Railroad, merged with its longtime rival, the New York Central Railroad, to become the Penn Central, which declared bankruptcy two years later and sold off the DT&I to private investors. In 1980, the DT&I was acquired by the Grand Trunk Western Railroad (GTW). Under the GTW, the DT&I locomotives were painted in the red and blue livery of the GTW, but retained the DT&I logo. In December 1983, the DT&I was completely assimilated into the GTW. End of service on southern portion In April 1982, a collapse in Royersville Tunnel (the only tunnel on the old DT&I) prompted GTW to shut down the line between Jackson and Ironton. The tunnel had suffered collapses many times in the past but limited remaining business south of Jackson and the operational problems of the tunnel led to GTW's decision. At the same time, GTW bypassed the steep and treacherous Summithill section between Bainbridge and Waverly by rerouting trains onto Chessie System trackage from Washington Court House, Ohio to Waverly, then back onto the former DT&I to Jackson. In 1984 all operations south of Washington Court House were suspended, the Jackson Shops closed, and the track dismantled. A short section of the DT&I main west out of Jackson is still in place serving as a connection from industries to the only remaining line into Jackson. A short section of the DT&I north from the junction with the B&O Southwestern near Greenfield is still in place to serve local industry. Portions of the line between Greenfield and Washington Court House were purchased by Washington Court House with the intention of creating a rail-trail, but they were unable to acquire enough conjoined sections to build a trail. Central and northern portions GTW continued to operate the northern and central portions of the former DT&I as part of their network for many years. The DT&I trackage from Springfield to Lurray (near Washington Court House) was sold by GTW to the West Central Ohio Port Authority (formerly Clark County - Fayette County Port Authority)