In the operation input device of the prior art, the input of a position and the input of an attitude are mixed up and both the position and attitude may be changed by the result of the input of a change in attitude. A DA conversion circuit is disclosed, including n resistors A0, A1,. The method uses initial parameters, input to the computer, to simulate railyard task flow utilizing a yard performance model. In one embodiment, the set identifier is received over an electronic network, a list of the presentation instruments in the set is accessed from a computer database, and each of the presentation instruments is activated.