Many probably think Iowa is flat, well the engineers working over the Mason City Sub in northern Iowa, may disagree. As seen here looking down highway 24 between Lawler and Jackson Jct., the 632 has just topped the 1% grade, and is about back up to speed as this engineer begins to brake for the downhill the next 2 miles, then it will be a workout for another uphill 1% grade into Jackson Jct. Gives the engineers a workout on this loaded trains.