If you listen carefully when
the LOCOMOTIVE disconnects,
The Big Bang Theory Season 7, Episode 15
U.S. LOCOMOTIVE
ever built?
The Big Bang Theory Season 7, Episode 15
I bought an N-gauge LOCOMOTIVE.
The Big Bang Theory Season 5, Episode 3
I hear LOCOMOTIVE smoke
is the second leading cause...
The Big Bang Theory Season 8, Episode 22
"You are running the LOCOMOTIVE."
(GASPS)
The Big Bang Theory Season 10, Episode 15