
If you knocked I couldn't hear you.
I'm welding this LOCOMOTIVE engine.
The Big Bang Theory Season 10, Episode 15

"You are running the LOCOMOTIVE."
(GASPS)
The Big Bang Theory Season 10, Episode 15

An Alcoa FA-4 diesel LOCOMOTIVE
The Big Bang Theory Season 7, Episode 15

So often, on the front of the LOCOMOTIVE...
The Big Bang Theory Season 8, Episode 21