I went to the fights, and a subway station broke out ...

... unfortunately I didn't get a shot of the fight that broke out between two guys on my way to work this morning. I was walking down a flight of stairs when I heard a woman scream, then caught a glimpse of two middle-aged men throwing fists at the top of an escalator.

One guy seemed to have the upper hand, and got a few final shots in while the security guards separated them.

Can anybody tell me what this sign on the subway floor means?

Note: The subway trains come in 6 cars and 8 cars, so the sign on the floor tells people where to wait/stand depending on the length of the next train (which is announced and also shown on a screen along with wait times).