Parts of the old NYC line do exist. Cincinnati to Indianapolis would need a lot of upgrading, but it is there. See link, https://www.gwrr.com/cind/. The problem is between Lebanon, Indiana and Lafayette as the only rail line that exists is the old PRR through Frankfort and is now CSK and NS. Indiana Railroad Map link. https://www.in.gov/indot/files/RailSystemMap_Med_StWide_11x17_RH_Final.pdf. From Lafayette to Kankakee, the line is in place. https://www.kbsrailroad.com/The Penn Central's James Whitcomb Riley prior to Amtrak was well patronized between Indianapolis and Chicago's Central Station via the former New York Central/Illinois Central route through Kankakee. Once the train reached the IC mainline at Kankakee, it would fly up the welded rail line and even if it was a little late arriving at Kankakee, it would on time at Central Station. It left Indianspolis mid morning and arrived in Chicago around 1PM. The return train left Central Station around 3:50PM and got into Indianapolis 8:30-9PM. It, of course, ran to and from Cincinnati. That continue at the beginning of Amtrak, but the Penn Central tracks deteriorated so the time keeping was horrible. For a while the train used the former C&O route which bipassed Indianapolis. The full former New York Central from Kankakee to Cincinnati doesn't exist. The State of Indiana should have bought this line for future high speed service. Unfortunately Indianapolis Union Station is a dinosaur left over from a bi gone era.