tables balanced on the railing

[Misakim]

Hi,

This is from an article titled Ristretto | Tokyo Coffee in Tmagazine in the NY Times. Can you help understand the part in blue. How come it is "tables balanced on the railing"?


Little Nap

An espresso bar wedged in between a community park and some railroad tracks, it’s a relaxed scene with good cappuccinos. There’s a Synesso on the counter, stools outside, brightly painted pink tables balanced on the railing across the street.

[riquecohen]

I would say that they're not really tables in the traditional sense, but tabletops anchored to a railing.