The Paul Henry - Thornapple Trail began its existence as the Grand River Valley Railroad. It was chartered on May 4, 1846 and then went into a state of dormancy for over 20 years. Actual construction of the 95 mile line between Grand Rapids and Jackson did not occur until 1868-1869. The tracks reached Hastings in April of 1869. The first train, consisting of the locomotive "Muskegon" and six cars arrived in Grand Rapids on January 1, 1870. Regular service began a couple weeks later on January 17. Finish work on the line lasted into the spring. The City of Grand Rapids had promised the Grand River Valley Railroad a subsidy of $100,000 for building the line but later paid only $25,000, according to an mutual agreement.
From its inception the line was controlled by the Michigan Central Railroad. Michigan Central made the line a branch of their system through a perpetual lease on August 15, 1870. Eventually the Grand River Valley RR was formally merged into the Michigan Central on September 15, 1916. The Michigan Central also controlled the Chicago, Kalamazoo & Saginaw RR which crossed the Grand Rapids-Jackson line in Hastings. This part of the CK&S was abandoned during the Great Depression of the 1930s. The giant New York Central Railroad owned a large percentage of Michigan Central RR stock. The New York Central consolidated the Michigan Central into their system on February 1, 1930 by leasing it for 999 years.
For nearly 40 years New York Central trains were a familiar presence in the towns along the current trail corridor. Passenger service which had been a daily train each way between Grand Rapids and Detroit in the 1920s dwindled down, in the 1950s, to a motorized passenger car called an RDC. New York Central called this service The Beeliner. Passenger service was discontinued when the last Beeliner ran in December of 1959. The line was relatively well maintained with speed limits of 60 mph for passenger trains and 40 mph for freights. Freight service in the 1960s usually consisted of a train from Jackson to Grand Rapids one day with a return run the next. New York Central merged with the Pennsylvania Railroad on February 1, 1968 to form the Penn Central Railroad. This was done with the intention of strengthening both railroads but had the opposite effect.
By 1970, Penn Central was in bankruptcy and track conditions and service deteriorated. Conrail was created to maintain rail service on parts of Penn Central and several other bankrupt eastern railroads. Conrail began operations on April 1, 1976. Conrail sold or discontinued service on many light traffic lines. Service was discontinued on the Grand Rapids-Jackson line east of Vermontville to Eaton Rapids. It did not want to operate the rest of the line either but agreed to do under contract with the State of Michigan which had leased the property from a holding company of the Penn Central which still owned it. Conrail did not renew their operating agreement with the state in 1979.
The Kent, Barry and Eaton Connecting Railway was formed and was awarded the contact and a subsidy to operate the line between Grand Rapids and Vermontville. It had the distinction of being the first minority owned railroad company in the nation. They began service on July 15, 1979. Traffic consisted mainly of grain, fertilizer, scrap metal and farm machinery. They hoped to rebuild the line between Vermontville and Charlotte to connect with the Grand Trunk Western RR but they could not accomplish this. A combination of inexperienced railroad management and failure to build traffic on the line led to its demise. The state ended its operating subsidy and service on the line was discontinued on October 15, 1983.