Great picture, I've stood on that balcony and walked down Signal Hill too! Greetings from England.
This is the only tunnel on the Katy Trail. It was built in 1893 by the Missouri-Kansas-Texas Railroad. This tunnel was also used in the Stephen King film "Sometimes they Come Back". The film was made after the origional tracks were removed and temporary tracks were put in place for the movie.
This picture is in Kearny, not in Newark. The Newark part was added by the system, not me. I certainly know better.