Test study on stability control of locomotive coupler in heavy haul combined train

To control the dynamic stability of locomotive couplers in heavy haul combined trains, a formula for calculating the maximum free swing angle of heavy-haul locomotive couplers was derived from the stability principle of the coupler and the geometric relation between the coupler and carbody on rails. Taking some locomotive driving a heavy train in Datong-Qinhuangdao line with coupler & draft gear DFC-E100 as an example, the effect of the lateral swing of the coupler for the middle locomotive on locomotive operation security was studied by tests. In the tests, the coupler longitudinal force was increased gradually by changing the haul weight, organization mode, and braking mode of the train, and the security parameters such as locomotive derailment factor, wheel unloading rate, and lateral wheelset force were measured in different operating conditions. The results show that the lateral swing angle of the locomotive coupler would increase with the coupler longitudinal force under the action of coupler pressing force. The bigger the maximum lateral swing angle of the coupler is, the bigger the security parameters of the locomotive are, and the bigger the risk of locomotive derailment is. With engineering errors taken into consideration, the maximum free swing angle of the locomotive coupler should be controlled in the range of 2.5°~3.5°.