The Louisiana Public Service Commission shall require all railroads, and other common carriers doing business in Louisiana, upon the demand of any person to adopt, make, and change, reasonable and just joint through rates and charges for the transportation of freight between points within this state, whether those shipments are made entirely by railroads or by water transportation, or partly by railroads and partly by water, or whether, when made by railroads alone, such freight is forwarded in carload shipments or less.
La. R.S. § 45:1093