Camden has an active line bisecting the course which comes into play on two holes (3 on the original Travis routing).
Originally the opening hole, the line runs along the outside of the short, dogleg par5 13th. For member events and the CGA FourBall, it's played as internal OB, with the roadbed right of way ONLY being OB. Blow it over the tracks into #14 corridor, and you're back in play. When we've hosted USGA events, they've played the roadbed as an immovable obstruction from which relief is allowed (I don't like either option..... I think it should be played as OB on shots in the roadbed and beyond).
The 1923 Travis routing had this hole playing as a mid-length par 4 (the green was 70 yards short of the current site), with a short 4 second where the tee shot was played over the rail line. Donald Ross eliminated this hole in his 1939 renovation, expressly stating that the intent was to eliminate shots over the railroad.
At one time I had an old article describing a match which was being delayed by "an especially slow moving freight." One competitor became frustrated with the delay and decided to hit over the train...... He hit the shot thin and watched in dismay as the ball clearly wasn't going to clear it, only to be amazed as it passed through a boxcar with both doors open.
I've hit a moving train several times, with both good and bad results (going the right direction, I got an unbelievable "turbo boost).
Jamey