Nicole -
The value in the TS.StartTime is similar to the Seconds expression function. You can use the Date and Time expression functions to convert the output of Seconds to a formated string or individual values. The key is to pass the seconds value to parameter 6 and True for parameter 7 of the Date or Time functions.
If you want to know when the engine started, you can determine this by calling the expression: 'Seconds(False) - Seconds(True)', or using the API by calling 'Engine.SecondsSince1970UniversalCoordinatedTime() - Engine.SecondsSinceStart()'.
Scott Richardson