For K1, K2,K3,K4,K5,K6,8A Y25 bogies Manufacturing ... and external spring2.Materials: 60Si2Mn, 60Si2MnA, 60Si2CrVA, and 60Si2CrVAT3.Usage:bogie of K2,K4,K8,Y25 with axle load of 21t ... the springs but also other related railway products such as bogies, wheels&wheelset,which reduce cost for buyers.4.Multiple choice of ...