Enumerate consecutive numbers in a repeat groups of questions

What is the problem? Please be detailed.
I want to list a field in a form with consecutive numbers within repeated groups of questions. For example, I have 25 stations and I need a form to take station 1 and the next station automatically take number 2 in a group. How I do this?

Anything else we should know or have? If you have a test form or screenshots or logs, attach here.

You can calculate that number using position(..). Please take a look: text1.xlsx (6.7 KB)