Findings From Wayside Measurements of Steered and Unsteered Freight Car Trucks in Coal Service

Prototype versions of the RESCO Steered Frame Truck were operated through a section of revenue track at Louden, TN, which has been outfitted as a wayside measurement site. The site contains several different measurement stations, which record lateral forces, angles-of-attack, etc. The site routinely measures revenue trains passing along that section of track. A test car, fully loaded to 286,000 lbs and fitted with the steered trucks, was operated through the test site a substantial number of times. The results from this testing were compared with data from standard 3-piece trucks and also from premium M-976 trucks, both in revenue service trains, from the same test site. It was found that neither the premium trucks, nor the standard 3-piece trucks, showed any significant steering through the ∼5° curves at the test site. The premium trucks did show a tendency to be more ‘square’ in the curves, although there were still substantial numbers that showed significant ‘warping’ behaviour. By comparison, the steered trucks showed virtually perfect steering and alignment behaviour. This was impressive in itself but was more so when it was found, after the test was concluded, that an interference between the truck and a bracket on the car body had prevented full rotation of the steered truck throughout these tests.