Okay, the user wants me to translate "drive train" into Japanese. Let me think about the correct term here. "Drive train" in mechanical contexts usually refers to the system of components that transmit power from the engine to the wheels. In Japanese, this is commonly translated as "駆動系" (kūdō kei). I should make sure there's no other possible translation that might fit better depending on the context. Since the user didn't provide additional context, "駆動系" is the most accurate and standard term. Also, checking if the original content was in Japanese, but since it's "drive train" in English, I need to translate it. No explanations, just the translation. So the answer should be "駆動系".