![If you knocked I couldn't hear you.
I'm welding this locomotive engine.
If you knocked I couldn't hear you.
I'm welding this locomotive engine.](https://content2.mcqstudy.com/ss/tbbt-10-15-00:09:31.864.jpeg)
If you knocked I couldn't hear you.
I'm welding this LOCOMOTIVE engine.
The Big Bang Theory Season 10, Episode 15
![I hear locomotive smoke
is the second leading cause...
I hear locomotive smoke
is the second leading cause...](https://content2.mcqstudy.com/ss/tbbt-8-22-00:11:39.165.jpeg)
I hear LOCOMOTIVE smoke
is the second leading cause...
The Big Bang Theory Season 8, Episode 22
![So often, on the front of the locomotive...
So often, on the front of the locomotive...](https://content2.mcqstudy.com/ss/tbbt-8-21-00:07:07.882.jpeg)
So often, on the front of the LOCOMOTIVE...
The Big Bang Theory Season 8, Episode 21
![and I get to operate an actual locomotive.
and I get to operate an actual locomotive.](https://content2.mcqstudy.com/ss/tbbt-10-15-00:04:56.297.jpeg)
and I get to operate an actual LOCOMOTIVE.
The Big Bang Theory Season 10, Episode 15
![I bought an N-gauge locomotive.
I bought an N-gauge locomotive.](https://content2.mcqstudy.com/ss/tbbt-5-3-00:17:41.613.jpeg)
I bought an N-gauge LOCOMOTIVE.
The Big Bang Theory Season 5, Episode 3