| | The capabilities of existing commercial NDT technology for rail testing reflect primarily the inspection needs of today's revenue railroads.The objectives of these companies, however, diverge from that of the Army.For instance, revenue railroads at present have wheel loads which are limited to 40 tons, and use rail weights that can be in excess of 132 lbs./yd.In addition, the rail defects that can cause commercial derailments - and for which the FRA requires regular inspection - tend to be those found in the head and web of the rail.Consequently, reliable commercial testing techniques are readily available to locate and quantify such defects as vertical split heads, transverse fissures, and horizontal split heads - but not rail base defects.This is understandable since the quality high-speed mainlines that make up much of today's revenue track constitute structural systems that act like the theoretical 'fully-supported beam on an elastic foundation,' often assumed as a track model. |
