Check the page because it has impressive photos. This station is in the Joetsu line, and has one platform at ground level and another at 70 meters under ground, in the middle of the Shin-Shimizu tunnel!!!!
You have to walk 486 steps to get to the platform, you can see the number written:
I haven't been there, but being part of the JR railway network I'll visit it next time for sure!! Looks mysterious and interesting enough.