If you knocked I couldn't hear you.
I'm welding this LOCOMOTIVE engine.
The Big Bang Theory Season 10, Episode 15
I bought an N-gauge LOCOMOTIVE.
The Big Bang Theory Season 5, Episode 3
So often, on the front of the LOCOMOTIVE...
The Big Bang Theory Season 8, Episode 21
and I get to operate an actual LOCOMOTIVE.
The Big Bang Theory Season 10, Episode 15
An Alcoa FA-4 diesel LOCOMOTIVE
The Big Bang Theory Season 7, Episode 15