CHAMBERLAIN, S.D. (AP) — Record crop yields and the North Dakota oil boom have led to a resurgence of rail transit in South Dakota, and it's Lynn Kennison's job to make sure the tracks are safe. The latest is a $28 million project to repair a roughly 42-mile section of mostly derelict track from Chamberlain to Presho, which has spurred tens of millions of dollars in agricultural development.