I remember when this sign was posted in the fall of 1989, visible from the commuter train window whenever I rode by. I was in college then, taking the train from Philadelphia to the suburbs every few months. It seemed strange to me that someone would go through the trouble to print a sign announcing that a gate was going to be locked on a certain date. I was also very dubious of anything described as "permanently."
In this case, "permanently" lasted until sometime in the 1990s when the gate was once again unlocked. I figured the sign would come down soon after, but up it stayed. Every time I took the train, I checked to see if it was there. By 1999, the gate had been unlocked longer than it had been locked and I thought the irony would make a great photo.
Try as I did, it was never convenient to walk to the spot where the sign was and it was impossible to get a decent picture from the train. I pretty much ignored the sign in the 2000s as I lived my life and got married. My interest renewed in 2009 when I realized that the sign had been up for 20 years, or half of my life so far. Finally, in 2017, almost 30 years after the sign went up and over 20 years since the gate was unlocked I got the shot above!