Well, Sheldon was going on and on
about time zones and RAILROAD schedules,
The Big Bang Theory Season 9, Episode 16
...an outdoor museum
featuring 43 RAILROAD engines, cars...
The Big Bang Theory Season 4, Episode 6
down by the RAILROAD tracks."
Breaking Bad Season 2, Episode 12
...a hot dog stand
in a converted RAILROAD dining car.
The Big Bang Theory Season 4, Episode 6
You'd have to drive a RAILROAD spike into
his brain for me to beat him at checkers.
The Big Bang Theory Season 2, Episode 11