Image reference in the Countermeasures downloaded file

The file regarding the Countermeasures that I downloaded, for example, star rates 1 & 2, have the Image reference: 24/125/1426/400 or 24/121/1426/500.

What do these numbers mean? I have all the survey images and would like to trace them in those Image folders.

24? Section of the road

125?

1426?

400, I suppose 400m

I appreciate your help in advance.

Image reference is the information you provided in the image reference column in the upload file.