Technical Reports

Gas-Spray Repair of Rail Surface Defects

  • 01
  • Oct
  • 1991
AUTHOR: Richard P. Reiff, Glenn Brave
SUBJECT: Facilities & Test Equipment, Rail and Infrastructure Integrity
KEYWORDS: Electric Flash Butt Welds, Thermite Welds, TTC, Japanese National Railways
ABSTRACT: An alternative weld repair process (gas-spray) was devised by the Japanese National Railways (JNR) which incorporates a oxyacetylene flame and a powdered filler metal. The gas-spray process was designed to operate either semi-automatic or fully automatic and was intended to reduce operator errors similar to manually welding with an electic stick arc. In the spring of 1984 at the Facility for Accelerated Service Testing, Transportation Test Center (TTC), Pueblo, Colorado, two JNR gas-spray build-up test welds were made on standard carbon rails on the inside and outside rails of tangent track in the High Tonnage Loop. As a base comparison, two TTC electric arc build-up welds were made a few feet away from them. Both weld processes were intended to simulate a build-up repair of an .080-inch-deep engine bum defect. A battered weld also was repaired with the JNR process in the low rail of a 5-degree curve at the testing facility. The repair welds were tested for a period of 60 MGT under a fully loaded train of 85 cars (33,000 lb wheel load) and four locomotives. After 60 MGT, the JNR welds showed signs of rapid wear and were then removed for evaluation. At the same time, the TTC welds also were removed. A wear rate of .050760 MGT was determined for the JNR welds. The TTC test welds located near the JNR welds displayed very little wear and retained most of the original build-up material. The other JNR weld intalled in the 5-degree curve revealed severe wear at 50 MGT and by 60 MGT the original weld deposit was barely visible.