Even the train example or the bridge example.
I don't know how to set to get a counter example automatically when it is not satisfied.
Tutorial on uppaal does not mentioned anything about it.
Please help me...Thank you very much.
Did you checked the option in menu:
Options -> Diagnostic Trace -> Some
? (or anyone except "None")
By default it is not checked, and it is tricky for a newbie to understand that without it the counterexample is not generated.
Wouldn't be better if Uppaal, by default, did generate a counterexample?