TIL upgrading your belts makes them MORE flammable — so I made a mod

I was digging through the game's prototypes while building an armored belt mod and found this:

yellow belt 150 HP fire 90%
red belt 160 HP fire 50% <- drops
blue belt 170 HP fire 50%
turbo belt 170 HP fire 50%

The basic yellow belt has 90% fire resistance. The moment you upgrade to red it falls to 50% and stays there forever. The normal progression of the game makes your fire resistance worse while you think you're upgrading.

There's more: no belt in the game has any explosion resistance at all. Not one tier. The field simply doesn't exist in the vanilla prototypes.

The second finding changed my mod's design. I pulled the actual offensive damage types off the enemies and there are only two: physical (biter melee) and acid (spitter and worm spit). No fire, no explosion. Which means fire resistance doesn't protect you from biters — it protects you from YOUR OWN flamethrower turrets torching your belt line, your own artillery, and tree fires. Which is what actually eats a frontline belt in practice.

So the mod ended up with all four resistances:

Armored Transport Belts
- Same speed as express (0.09375) — not a speed tier
- 600 HP per segment instead of 170
- Fire 95%, explosion 80%, physical 60%, acid 60%
- Hand-craftable: 1 express belt + 4 steel
- Unlocks after logistics-3 and military-3

It survives roughly 10x longer than express against behemoth biters, 19x against medium ones.

Two design calls I think matter more than the numbers:

It's a side-grade, not a higher tier. With Space Age, turbo belts already sit above express — making armored belts faster would have obsoleted a whole expansion tier. They keep express speed and only change survivability. You trade throughput for armor, you don't get both.

It keeps fast-replace and has no upgrade target. You can lay armored belts straight over an existing frontline without tearing it down, and no upgrade planner will move them afterward.

Before starting I checked the full mod portal index (22,942 mods). There are mods that make belts invincible with a toggle, and mods that add speed tiers, but none that treat the belt as defensive infrastructure. If I missed one, tell me.

Balance feedback very welcome. My main doubt: the flat physical damage reduction makes small biters unable to hurt it at all. The tech is mid-to-late game so I think it's fine in practice, but I'll admit it sounds strong.

It's my first mod and contribution to the community. I hope you like it and I look forward to feedback from you.