A dead axle of a rail vehicle, a rail vehicle, and a rail transportation system are provided. The dead axle of a rail vehicle includes: an axle body; a running wheel; a guiding frame; a horizontal wheel; and a connecting rod component, including a first transverse pull rod and a second transverse pull rod, where when the rail vehicle turns left, the horizontal wheel cooperates with a rail beam to drive the guiding frame to swing and drive the first transverse pull rod to move together, and the second transverse pull rod is driven by the first transverse pull rod to drive the running wheel to swing to the left, and when the rail vehicle turns right, the horizontal wheel cooperates with the rail beam to drive the guiding frame to swing and drive the first transverse pull rod to move together, and the second transverse pull rod is driven by the first transverse pull rod to drive the running wheel to swing to the right.