more fully below with reference to the accompanying figures which form a part hereof and show by way of illustration specific exemplary embodiments these embodiments are disclosed in sufficient detail to enable those skilled in the art to practice the invention however embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein the following detailed description is therefore not to be taken in a limiting sense in that the scope of the present invention is defined only by the appended claims in the drawings the numeral 10 refers to a conventional railroad track having rails 12 and 14 supported on ties 16 the numeral 18 refers to a conventional locomotive which is adapted to move along the track 10 in conventional fashion although it is preferred that the track vehicle 18 is a locomotive other track vehicles such as a high rail vehicle or a cargo car could be utilized the primary reason for using a locomotive is that it will have a greater weight than high rail vehicles or cargo cars so as to cause maximum deflection of the rails 12 and 14 when the locomotive passes thereover in one embodiment a conventional gps receiver 20 is secured to the top of the locomotive 18 so that it may receive data from a plurality of satellites 22 in an unobstructive fashion preferably the gps receiver 20 is centrally positioned with respect to the rails 12 and 14 to provide data for the center of the track 10 the height of the gps receiver 20 above the rails 12 and 14 will be determined in conventional fashion so that the data received by the gps receiver 20 may be adjusted to subtract the height of the receiver 20.