So often, on the front of the LOCOMOTIVE...
The Big Bang Theory Season 8, Episode 21
If you knocked I couldn't hear you.
I'm welding this LOCOMOTIVE engine.
The Big Bang Theory Season 10, Episode 15
An Alcoa FA-4 diesel LOCOMOTIVE
The Big Bang Theory Season 7, Episode 15
U.S. LOCOMOTIVE
ever built?
The Big Bang Theory Season 7, Episode 15