Abstract: Normal bogies of trunk locomotives are not fitted to the switching services on the curve line with small radii. With the increasing of the axle load, this case is getting worse. The technical characteristics and the test results on the bogies of the diesel locomotives used on mountainous areas and heavy mineral fields are introduced in this paper. A dynamics analysis for a heavy switching locomotive is provided, with improving measures for the locomotive are investigated. The theoretical calculation and the field tests show that it is profitable for the curving behavior to adopt roller friction side bearers, meanwhile, some succeeded experiences of bogies should be used to develop the heavy switching locomotive.