“ Two loaded coal cars coming from without the state were received in the carrier's yard at Fort Wayne, Indiana. They were destined to Olds' private switch track connecting with the yard; and, acting under instructions, Donat commenced the switching movement requisite to place them thereon. There was evidence tending to show that, in order to complete this movement, it became necessary to uncouple the engine from the loaded cars and with it to remove two empty ones from the private track. While engaged about the removal, defendant in error was injured. ”