The Secondary Instrument is collimated, or sighted back and aligned to the Base Instrument. Since the Base Instrument has been setup on the Offset Tram Line, the two instruments are now parallel with each other and perfectly aligned to the Offset Tram Line. Whereas the Base Instrument remains stationary, the Secondary Instrument moves freely to any point on the Offset Tram Line; thus, allowing us to establish the true position of a machine component relative to the machine as a whole. This method of collimation between two instruments produces faster and more accurate results.