The Case of the Refurbished Railcar
Railcar refurbish operations required a quality assurance process for examinations and testing structural castings for railcar frames, bolsters, planks and spring seats. The large, used castings were thoroughly cleaned of debris, grease and scale, sandblasted and examined by Visual Testing (VT) and Wet Magnetic Particle Testing (MT). VT and MT were performed by qualified personnel on the accessible areas of each casting. When relevant indications (discontinuities and cracks) were located, the areas were repaired by certified welders and retested.
VT and MT results were required to meet the acceptance criteria of AMTRAK Standard Maintenance Procedure 46617. When discontinuities and cracks were located, the indications were carefully removed by grinding or arc-gouging and repaired by SMAW welding with low-hydrogen electrodes. After weld repairs on any casting, post-repair examinations were performed. The post-repair assessments were to confirm that the refurbished casting met the VT and MT acceptance criteria of the AMTRAK standard.
Primary casting indications and surface cracks were of concern in areas likely to affect the structural integrity of supports on the refurbished passenger railcar. Surface flaws on the castings included ridges, cracks, cluster porosity, and sharp edges were marked, mechanically removed and repaired by welding. VT and MT examinations of smoothed regions and weld repairs on each casting were examined by methods prescribed in AMTRAK Standard Maintenance Procedure 46617 guidelines.
The Lessons Learned:
After cleaning, sandblasting and preliminary VT and MT with subsequent re-examinations, refurbished castings were accepted. When Certified Level III technicians and Supervisory personnel accepted the refurbished castings to the standards, Engineering concurred and the refurbished casting was returned to service.