Station Stop

In your testplan you can place a LTT Station Stop whenever you want to actively stop the test execution of this station. Of all stop criteria, this is the only active one, where you, the testplan developer, decide when to stop. That's also the reason why a station stop is usually accompanied with a step precondition.

TS Req Stop

Normally, there is rarely a need to actively stop a test from within the testplan. However, if you do so, be aware that the station stop does the same as if a user would have pressed F1 or F8. You still need a check for stop step hierarchy to actually stop the execution.