Railgun

A large metal bridge spanned the river, about 150 meters across,
and no cars could be seen on it.

***

“Zero, you say,” repeated the girl as if she was turning it over in her mouth. She stuck a
hand in her skirt pocket and pulled out an arcade coin. “Have you ever heard the term
Railgun?”
“Ahn?”
“The idea behind it is the same as a linear motor train. It is a ship-borne weapon that
uses powerful electromagnets to fire a metal projectile.”
The girl flicked the coin up into the air with her thumb. The coin rotated a few times
before landing back onto her thumb.
“It refers to something like this.”
Just as she spoke, an orange spear of light suddenly and silently shot past Kamijou’s
head. It was more like a laser than a spear. He could only tell it had originated from the
girl’s thumb because the afterimage of light stretched back to it.

Almost like thunder, the noise rumbled in with a slight delay. As a shockwave tore
through the air around his ears, Kamijou’s sense of balance was partially destroyed. He
staggered and glanced over his shoulder.
The instant the orange light struck the road surface on the bridge, the asphalt was blown
away like an airplane making an emergency landing on the ocean. Even after travelling a
30 meter path of utter destruction and stopping, the orange afterglow was still burning
the air like an afterimage.
“Even a coin like this can be quite powerful when it's fired at three times the speed of
sound. Of course, the coin melts after 50 meters because of air friction.”
That bridge made of steel and concrete swayed like an unreliable suspension bridge.
Failing metal bolts could be heard occasionally.

- Toaru Majutsu no Index Volume 1, Prologue