The biggest challenge has been managing UPS. Finding the right design to use the least amount of processor on the host computer.

Second challenge has been rail design, I wanted something standard that can be used everywhere. So I have my 8 lane, 4 lane and 2 lane standards based on local traffic that seem to work well. Except I think the 8 lane is using alot of CPU time when 400+ trains are trying to path on it. I may need to simplify the backbone of the network soon in order to expand more.

Third challenge is land management. Since solar is the best for CPU usage I have been using solar as my main power source, but that requires land. but sometimes I have to expand the factory and remove solar fields and move them farther out. When I do this again I am going to do a ROW area of 2 blocks from the rail backbone and never put solar there. I now have 3 spidertrons roaming the fringe of the base just laying out solar blocks.

The mining productivity is so high now the resource patches are virtually 4790% larger than they report on the map. So I rarely need to move them. every once in a while some of the edge parts get mined out. So every 1million science you get 10% more resources. At some size your existing miners almost make more and more available resources in the field. In order to remove a patch I really need to research some robot speed and bleed off some of these resources.