The midwest is home to some of the biggest infrastructure machinery and mining companies in the world. From Caterpillar to John Deere, Cummins to Joy Global. These are all based in the Michigan, Wisconsin, Illinois, Iowa, & Indiana region. These all engineer and manufacturer their halo products in their home states too. Mining trucks in Decatur, bulldozers in Peoria, wheel loaders in Aurora, mining shovels in Milwaukee, etc, etc, etc.
Then add in the coal available under Illinois. The massive farmland available in this region. The oil refining plants. Excess fresh water supplies. And enormous networks of navigable waterways. [I think folks who grow up out west don't quite realize how much excess water we usually have around here.]
Would an EMP halt the machine shops and foundries in this region, of course. But I would think some of us engineers & metallurgists & machinists & assemblers with massive manufacturing footprints and years of experience in these states would be able to figure out some solutions to post-apocalyptic infrastructure problems. Peoria alone has 3 active foundries in the area of various scale, and a dormant 4th not too far away. Who knows what the rest of the state has. This industrial city is an island of manufacturing in a sea of farmland and grain silos, split in half by a 1/2 mi wide river.
Also realize that we still have full production lines that build mechanical diesel engines. Off the top of my head I know of plants with this active production in the US, UK, India, Japan, and China.
Methanol can be used as a gasoline substitute distilled from wood.
DME is a diesel substitute made from methanol.
Or coal can be gasified to whatever syn fuels, plastics, and rubbers are needed - using 1930's tech.
blah, blah blah...
If you aren't familiar with America's infrastructure and manufacturing industry, then you don't understand that we aren't as helpless as fiction makes it out.
