lmaotrain

Definition: Commonly used when describing a state of intense laughter.
The person laughs so much that it feels like a train is hitting them.

History: First used by the signal changers on the railways in the southern states of America. The expression was used after the signal changers used to incorrectly change the lights to confuse trains. They used the expression ‘lmaotrain’ after a train, due to his intense laughter, hit one of the employees.