Ind. Code § 8-8-1-1
It shall be unlawful for any common carrier engaged in moving traffic by railroad between points within this state to use on its line any locomotive in moving such traffic not equipped with power driving wheel brakes and appliances for operating the train brake system, or to run any train in such traffic that has not seventy-five (75) per cent of the cars in such train equipped with power or train brakes, and having the brakes used and operated by the engineer of the locomotive drawing such train, and all power brake cars in such train shall be associated together and have their brakes used and operated: Provided, That this section shall not apply to the handling of trains or cars in yard service, or to a local train while engaged in performing switching service.
IC 8-8-1-1