Experimental investigation on the dynamic performance of a heavy haul locomotive and its coupler and buffer system under longitudinal forces

This paper presents a systematic experimental investigation on the dynamic performance and compressed stability of heavy haul locomotives under longitudinal forces for the first time. A series of 10,000-tonne heavy haul train field tests with different locomotives traction in the head are designed and conducted under the same conditions of line and operation. Four different kinds of heavy haul locomotives are choosen and tested in turn. They have different structural parameters and are equipped with the 100-type flattened pin or 102-type cylindrical pin couplers respectively. The testing content includes the train passing through 12# turnout branch line and running on the long downhill line with locomotive electric brakes. The dynamic responses of the second locomotive in the head and its coupler and buffer system are measured and analyzed. And then the mechanism and influence law of the coupler types and locomotive structure parameters are investigated comprehensively. Results indicate that the cylindrical pin coupler has the better deflection direction followability with the curve direction variation than that of the flatten pin coupler, and thus is more conducive to the locomotive running safety of curve negotiation under longitudinal compressive forces. Both locomotive secondary lateral stiffness and lateral stop have a significant effect on the system compressed stability, and the matching relationships between these suspension parameters and the two types of couplers are different. By the reasonable optimization of suspension parameters, both the locomotives equipped with the flattened pin or cylindrical pin coupler could maintain a good compressed stable state under the normal longitudinal forces of 1000 kN, and have little difference in their dynamic performance.