Chief Engineer, Rail Welding Group,
Track Technology Development Department
Mitsumasa TATSUMI
Engineer, Rail Welding Group,
Track Technology Development Department
Makoto ISHIDA
Manager, Track Dynamics Laboratory
Railway Technical Research Institute (RTRI) signed a contract with Association of American Railroads (AAR) in 1995. In the contract, AAR agreed to provide the facilities and resources necessary to conduct or support the testing on RTRI-provided equipment and/or material at the Transportation Technology Center (TTC), Pueblo, Colorado. As a first test, the accelerative test of rail gas pressure welds was started at the Facility for Accelerated Service Testing (FAST) High Tonnage Loop (HTL) in March 1996 (Figure 1). The objective of this test is to obtain some data on welded rail end batter (WREB) of Japanese Industrial Standard (JIS) 60kg standard carbon rail in track, thereby to establish the maintenance and control methods for longitudinal rail profile on running surface. The WREB has an effect on the fatigue strength of rail weld, and causes running noise and track vibration during train operation. The two 25 meter long JIS 60kg rails containing three gas pressure welds on each rail, which were executed under various welding and postweld heat treatment conditions, were installed in section 5 of FAST HTL (Figure 2); these weld rails were joined with 136lb head-hardened rails by compromising alumino-thermic welds (Figure 3) and located on tangent track on both sides (Figure 4). At the present HTL, train operation is bi-directional under 39-ton heavy axle loads, and the gross tonnage passed is about one million gross tons (MGT) per day. In this test, longitudinal rail profile and hardness on running surface at each weld as the static data, and vertical force, bending stress and vibration acceleration at two selected welds as the dynamic data are measured at 0, 10, 25, 50, 75 and 100 MGT. The test plan is set for about one year.