I will try to explain as best I can. Maybe someone from the area will see this someday so I'm putting up here. Ok. So that wall there is an apartment building. It used to have a big painted sign saying "Bachelor Apartments" It used to look pretty seedy on the other side and local parents told their kids to stay away from it and the people who lived there. I think they were probably exaggerating it.
So I always wondered why there are no windows on this side? It faces the beach and would have a great view of Anaheim Bay. A billion years later I found out about the vacant space. It was a railroad track. I'm guessing the builders figured nobody wanted a view of that. It's probably quieter inside too.
It looks like the developers will get their wish and build some super expensive box homes. So this may be the last of this bit of open space. Thanks for your time. :)