美国联邦铁路管理局选定八种转向架在TDOP(货车转向架优选计划)第二阶段进行运行试验。这项试验于1979年10月开始,以鉴定这些转向架通过独特的设计方法所能达到的各种性能水平,从而为制定专用货车转向架和标准三大件转向架的试验规范提供依据。现将这八种转向架简介如下: 1.Dresser DR-1导向臂径向转向架 The United States Federal Railroad Administration selected eight bogies for operational testing during the second phase of the TDOP (Truck Bogie Optimization Program). The test began in October 1979 to identify the various performance levels these bogies could achieve with unique design methods that provided the basis for the development of test specifications for a dedicated truck bogie and a standard three-piece bogie. Now these eight kinds of bogies are as follows: 1.Dresser DR-1 guide arm radial bogie