Behind the Yellow Line (1984)

Lesile is a young guy that uses the MTR everyday, and one day, he sees a beautiful lady (Maggie Cheung) on the train and likes her immediately. On the other hand, he also knows a tomboy (Anita Mui) on the train too (and she likes him too!). Then, with side-kicks like Chan and others the chase of love in the MTR system begins.