Indiana traffic law question: Is passing stopped traffic in order to turn left illegal?

Is this situation illegal? There is a train crossing on the tracks and traffic is stopped and backed up. We would like to turn left at an intersection before the crossing. To do so we need to cross double yellow lane markings to turn left and pass about 5 cars that are waiting for train. After carefully checking for oncoming traffic and proceeding slowly (10 mph) and carefully we do so.