This mod had Bob's support
https://mods.factorio.com/mod/Subterrain

If you could, Bob's adds three new tiers of belts. One "basic" which is lower than yellow and bumps the rest up by one. Then purple and green which are quite fast. Would be great to add to this mod since the 0.16 version had it.

I'll take care of this within the next days.

Hi Recon777,

I'm thinking about removing the subterrain belts and replace them with their corresponding vanilla variants. I would like to have in future no additional items, rather I would like to see that the vanilla underground belts behave the same as the belts added by this mod. How do you think about this?

Are you talking about essentially taking over NORMAL underground belts and making them behave like Subterrain belts?

If so, ABSOLUTELY NOT! There is a critical flaw in the Subterrain belts in the fact that they cannot be blueprinted or deconstructed by bots. This is tolerable for limited use long-distance stuff where you put down Subterrain belts for in-base infrastructure. But for BUILDS... actual blueprints of things, Subterrain belts are completely broken. They do not work. And because of this, the non-Subterrain underground belts MUST be kept in the game.

Additionally, it is not super high priority at this time to make the fastest tier of Bob's belts probably because they already have a pretty long range underground and are fine in most situations.

I see the issue and tried addressing it without success yet. I disabled ghost building of the entities.

Just an idea but make the extra long underground belts very slow and pipes and 10x more expansive... i think to not be too OP they may function as supply to a defensive outpost or transport to a very small production site .