Engineers are actually pretty good at making new blueprints.
In fact, they already did it once. Coal-fired steam engines powered civilization once, and could easily do it again. Probably better, using modern techniques such as fluidized beds, pelletizing, etc.
There's this perception that oil will some day "run out" suddenly, like the last sip at the bottom of a milkshake.
It doesn't work that way. If it happens, oil will gradually become more expensive, until the point where it becomes more economic to use coal (or fission, or fusion, or whatever). At that point, the amount of oil remaining becomes moot.
Blueprints for how to make a tractor won't help if the blueprints assume gas or diesel fuel, and there's no oil any more...