Books aren't gone, most cities seem to be intact. Hell, Monroe is based in Independence Hall.
An organized force like the Monroe Republic should have been able to get steam power back into general use fairly quickly. There are plenty of steam locomotives still running today and there are entire museums dedicated to the preservation of steam engines. Steam locomotives and engines are fairly simple devices in all honestly. As long as they don't catastrophically fail, repair is not difficult.
It just seems out of the blue to me. This is the kind of thing that messes up shows for me. I'll still watch it, but it just won't feel right.