When is this set?

The US first train robbery was in October, 1866 by the Reno Gang near Seymour, Indiana, yet those details were pretty ambiguous in episode 1. It looks as though actual cases from the Pinkerton files are woven into dramatic liberties without being too specific to pin down any year. Safe to say the setting is first decade after the Civil War. For further Pinkerton action check out 1970's The Molly Maguires set in 1876 Pennsylvania.

1865 was fronted