that's gotta be the weirdest/coolest thing i've seen

I don't get it.

Why is the girl in the blue dress completely submerged when the school girl less than half way so....and the one in the far background not completely submerged as well?

It blows my mind, as it defies how any gravity would work. @.@

Look closely, and you'll see that every single person has their own water level. Who knows what it means?

こころしずめて、おもいうかべて
ぼくらは　それぞれの推移を

沈む（しずむ） seems to mean both "to sink" and "to feel depressed". Clever pool?

The station names: Modori, Tomari and Susumi mean Return, Stop, Continue respectively. And the final stations in both directions are Hazimari (Hajimari) and Owari, which mean Beginning and End respectively again.

Clever...?

Catamata said:
Why is the girl in the blue dress completely submerged when the school girl less than half way so....and the one in the far background not completely submerged as well?

Maybe it's water inside water.

Like in Spongebob Squarepants.

must be gobal warming.

Guessing from the comments, those water levels represent their depression levels.

And if that is true then the woman in the blue dress...

shiro123 said:

Guessing from the comments, those water levels represent their depression levels.

And if that is true then the woman in the blue dress...

... is ready to commit suicide.

Would make sense, if she's ready to jump into the train.