Complete the detailed specification of the train controller that was started in Section 1.4. Show all the required classes. Specify the behaviors for those classes. Use object diagrams to show the instantiated objects in the complete system. Develop at least one sequence diagram to show system operation.

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1.4 Design example: model train controller In order to learn how to use UML to model systems, we will specify a simple system, a model train controller, which is illustrated in Fig. 1.15. The user sends messages to the train with a control box attached to the tracks. The control box may have familiar con- trols such as a throttle, emergency stop button, and so on. Because the train receives its electrical power from the two rails of the track, the control box can send signals to the train over the tracks by modulating the power supply voltage. As shown in the figure, the control panel sends packets over the tracks to the receiver on the train. The train includes analog electronics to sense the bits being transmitted and a control system to set the train motor's speed and direction based on those commands. Each packet in- cludes an address so that the console can control several trains on the same track; the packet also includes an error correction code (ECC) to guard against transmission er- rors. This is a one-way communication system-the model train cannot send com- mands back to the user.