Conversation so far:
who did Edwin Booth save?
Abraham Lincoln's son, Robert, from serious injury or even death.
where did this happen?
The incident occurred on a train platform in Jersey City, New Jersey.
What caused this?
The incident occurred while a group of passengers were late at night purchasing their sleeping car places.
What happened next?
The platform was about the height of the car floor, and there was of course a narrow space between the platform and the car body.
Why did he fall?
There was some crowding, and I happened to be pressed by it against the car body while waiting my turn.
In this situation the train began to move.
How was he helped?
when my coat collar was vigorously seized and I was quickly pulled up and out to a secure footing on the platform.
What year was this?
1864 or early 1865.

Question: Did Robert Know him?
Self-contained rewrite: Did Robert Lincoln know Edwin Booth?