Two unrelated ideas
One is an alternative to the AAI miner (works well enough, I rely on it myself, as may be recalled).
It's essentially a train car that is placed in front of the locomotive and pushed into the wall ahead of it while placing tracks it has in a designated storage slot.
Maybe it also places supports at set intervals?
Potential inspo: https://cdn.discordapp.com/attachments/1337847981642354752/1374053297257844847/XRE_bodycopy_image1-1.png?ex=682ca65a&is=682b54da&hm=763a1a6ae10c64279b2e4ce2bcc15399c239d27239e69f303bfd8d14cfdfdb69&
https://cdn.discordapp.com/attachments/1337847981642354752/1374053181805301890/mf420-007.png?ex=682ca63f&is=682b54bf&hm=605584a1c0a769d293b83263aaa5f4252a20f34133c3325f29ceccd152e975f8&
(Functional inspo, really, I understand assets may be hard to come by)
Maybe loading it with floor tile materials and structured support beams could yield a more stable form of tunnel making this a great later-game subterranean expansion tool for whenever cave-ins or other challenges are added.
The other is possibly the scope of another mod, but the cool thing about tunnels is how you can manage air flow through them with relative ease, so I was thinking it'd be cool being able to blast pollution around the tunnels, downside being you need that clean air to come from somewhere too, but I could see this being too finicky or not taking the way the game handles pollution into account.
