Now that Railcraft is on 1.12 maybe it would be possible to get support for it please? (Rolling Machine + Crusher)

Be aware of Railcraft/Railcraft#1610. Until not all recipes are moved to init this could be a thing.

According to the old wiki, Railcraft was supported in 1.7.10. The Railcraft team has also apparently delegated this to ModTweaker in this issue.

Railcraft is very much still in beta, and as that issue said I can't actually do anything with their recipes right now.

If Railcraft gets a proper release, please feel free to create a new issue for this.