Post Office Third Branch

The Third Branch Post Office (第三支所 郵便局) is a post office located in School District 7. A modern postal service facility with ATMs, it is notable for being the location where Shirai Kuroko first test her mettle in the field.

Background
It is a modern facility with a modern look. It has shutters that closes down automatically, and summons a Security robot at a push of a button.

Toaru Kagaku no Railgun
The location is the scene where Shirai Kuroko is forced to confront two robbers, who intend to rob the ATMs of their money. After easily beating the first one, the second one, being an esper, takes out the Security Robot who was summoned to confront him, as well as Konori Mii with his ability, Equal Speed.

He takes Uiharu Kazari hostage, and due to being surprised, restrains Kuroko. He later uses his power to create a hole for him to escape after she teleports Uiharu away, and would've harmed Kuroko with his Equal Speed, if not for the timely intervention of Misaka Mikoto. This allowed Kuroko to take him down and restrain him.