Well if you can leave it until it's 1/4 full, then let it go, then you should be alright.I tried in another Biome. It might work in wet type. I have set it up in a swamp biome near my town but i believe if i move to that location it will cause the town to not be loaded. I could just set up a mine there and base at the town. Anyone know if another biome would be wetter to railcraft then Spawm? Do towns in Mill spawn in wet biomes?
*Let it fill the pressure chamber thing (vat?) THEN the hopper, and then when the tank is about 1/4 full (about 100 buckets) you shouldn't have issues... unless you try to process a chest full of ores.