I do NOT include labor unions and labor associations in the railroad certificate database.

My logic is that while some unions used typical words associated with the railroad industry in their names ("locomotives", "conductors", etc), their businesses did not running railroads for their own profits.

Labor union profits came strictly from membership dues and their products were publications and collective bargaining.

While union members may have worked to increase profits of operating railroad companies, the unions themselves were often accused of working at cross purposes.