This guide will let you know how to gain access to 1 7 in Sonic Frontiers.
You will need to head over here to the Elder The Hermit and then interact with these posts.
You have to combine them, and they basically string to each other. When you activate this, it will draw a rail.
After that, just make a straight line, activate it, and jump on it. It’s an easier way to get on this rail. Once you get to the other side, you will get 1 7.