The 1000 mile is designed to make sure that integral equipment is in proper working order. While the Sunnyset does traverse 2700 miles, it changes power in NOUPT, and recieves a 1000 mile again in SAS. All trains MUST recieve the 1000 mile every 1000 miles or so. The 1000 mile is built into dwell time, and typically occurs at crew chenge points. Items that are checked in the 1000 mile include: headlights (high and low setting), ditch, markers (where applicable), Cab Signals (where applicable), computer functions, circuit breaker checks, and a whole bunch of other stuff. These are mandated by the FRA to ensure that the unit is functioning properly, and that it is to safety code. The train is not to be released until the train gets the 1000 mile.