"Groper Train" distributed by Shintoho.

An older woman is approached with an offer to marry a wealthy company president, even though she is the second wife. If she accepts, the company will arrange a luxury apartment for her sister and her husband, and the husband will also be a company executive, and the woman decides to accept the offer. One day, the woman is attacked by a group of three men and raped in the street, but a photo of the incident is taken by a young boy who happens to be a factory worker. The boy uses the photo to blackmail the woman, and plans to escape from his poor life if he can get money...

Every car on the train during school hours is packed. And as that happens, there are also a lot of gropers who are after them...

Pink film from Toei Central.