Chances are you'd either go into the freight car design and maintenance department or the locomotive department. After serving an apprenticeship-training period, you'd be put in charge or a small maintenance shop or assist in the management of a larger one. Your rersponsibility would be to insure that the railroad always had enough operable cars and locomotives to meet requirements and devise methods to accomplish that at the least expense while insuring that safety is always paramount. As your experience grows, you may be asked to serve on a design team to find better and cheaper ways to serve the railroads' customers, like new car designs or modifications of existing designs tohaul new commodities.