2015年4月15日発売の58thトリプルA面シングルから『青春小僧が泣いている』のアナザーバージョン(歌詞付き) 監督:渋江修平 Amazon⇒amzn.to/1GHUl7N Please note: this is a literal translation, the translation may not be perfect.
I love thinking about meanings to music videos lol so here's my theory: It starts off with the old gens cheering on the new gen when they get on the morning musume train, they see the old gen doing what they normally do and is offered to sit down and join them. When they join them and sit, they realize that things go really fast, and it scared them at first so they all run towards the back of the train and jump off. That was the wrong choice so it starts over. The old gen cheers them on again and the same thing happens, only this time when they're on top of the train, they have the old gen to help and guide them towards the front of the train. I guess it's symbolizing that by themselves, starting out in momusu may seem scary, but if they all work together things will work out-