Very cool Love them
"Original subway stations were pretty short, and they were soon extended for longer trains. But in some cases the extensions had to be built on curves, and the cars were too far from the platform in those locations, so extenders were installed."
This really isnt true The stations were curved from day 1. Until they stopped using it South Ferry had the platform extenders on a total of 5 car train They made announcements at the previous station to move to the first five cars as the back would not be open The platform extenders were there a long time and were the responsibility of the signal maintainers to make them work properly
