The teams, the Aguascalientes Mexicans and American Railways, played the first game in the state on the railroad's land.

The Rieleros were founded in 1975 by Raúl Medina Reyes in partnership with Don Pedro Barbosa, José Ortiz Benavides and other local entrepreneurs, who bought the Veracruz franchise and moved it to Aguascalientes.

The team debuted in the Mexican League on 14 March 1975 losing 1–5 against the Charros de Jalisco in the Parque Alberto Romo Chávez.

[5][6] With players such as Horacio Piña, Cecilio Acosta, Ángel Moreno, Willie Crawford, Clarence Jones and Chico Rodríguez, the Rieleros finished as leaders of the Southwest division with a 89–62 record.

In the quarterfinals, the Rieleros defeated the Diablos Rojos del México 4–2, including a perfect game by Piña.