Your recent posts do not substantiate any claim that the Federal government subsidized railroads with federal money.
the 1862 Transcontinental railroad act subsidized the Union Pacific and Central Pacific by giving them Federal land for the right of way and every other section of land along the right of way. . The Feds had been giving federal land to railroads for right of ways beginning in 1847. This land for right of ways was available to Southern railroads as much as it was to Northern railroads. The vast disparity of rail construction between North and South cannot be pinned on “Federal monetary subsidies”. Because there were none.
The Government paid railroads to haul government cargo. If the mail or cargo was bound for a destination in the South, a Southern owned railroad was paid to haul that cargo.
I have not made any intense efforts to locate any such information. I have only identified it indirectly by noting several articles that say they did. At some point I should be able to identify their sources for saying the Federal government was subsidizing railroads in the North, and then we will have found what *you* claim you want to see.