The United Railroad Historical Society of NJ recently posted a photo of inside the Wreck train crane they have rebuilt. Delmar did not have this model but it did have a wreck train unit with crane stationed here in Delmar.
see their facebook page for videos of it in action
From their page
Exciting news: Our Erie Railroad 160-Ton wreck crane can now be counted among our operating artifacts in Boonton Yard! This project was a labor of love by one of our volunteer mechanics, Erik Stenzel, who has been rebuilding components in his home shop over the past year. Check out his startup and operating demo in this video.