The three dynamics tests and their test conditions for the 120 km/h speed increased freight cars organized in our country are described. Analysis and summarization are made in view of the routine dynamics test and reliability test results for speed increased freight cars. And corresponding suggestions to solve the problems exposed in test are given. The three dynamics tests and their test conditions for the 120 km / h speed increased freight cars organized in our country are.. Analysis and summarization are made in view of the routine dynamics test and reliability test results for speed increased freight cars. to solve the problems exposed in test are given.