A dimension measuring system and method are provided. Two track reference target (TRT) assemblies are positioned at spaced-apart locations on a railroad track's rails. Each of the TRT assemblies has two targets at fixed positions in a plane perpendicular to the rails. For each of the TRT assemblies, at least one of the two targets is positioned at a known and fixed height over one of the rails. A laser-based distance measuring device measures vector distances to the two targets associated with each of the TRT assemblies. The vector distances are processed in combination with the fixed positions to determine an elevation of each of the rails in the plane associated with each of the TRT assemblies.