duskeyduskey
電車
Minor correction; it's not abandoned, it's simply a low-speed low-usage turnout for maintenance vehicles or a safety derail.
Building it this way - which as far as I can discern is unique to Japan - almost completely eliminates the costs of maintaining a regular switch while also allowing smoother full speed running on the main route.
There's a lot more discussion and information about those here https://www.reddit.com/r/trains/comments/cw0cqm/what_purpose_do_these_japanese_switches_serve_the/
I'm pretty sure the one used in the hanwa line isnt for maintenance vehicles.