This page is a soft redirect, which creates an searchable link title ('JA files') earmarked as a future topic and title, but temporarily redirects a user to a topic page and/or section of the Trainz Wikibook, which may at the moment give some coverage of the term (title of the article to come).

This page is a redirect to page section in the Trainz Wikibook.

This page is a redirect to a specific section of a Wikibooks Trainz page with topic being covered in the particular section on the targeted page receiving redirected links.

This page is a topic title which should exist as an topic page of Wikibooks Trainz page temporarily redirected to some other page or page section covering, at least in part, the subject matter of the title.
That is the title should have a topic page of it's own, as soon as someone can write one.