I also want to thank CH for putting their trainer out so fast. However I would have preferred the 1 day instant build option didn't make that factory 1 day for everyone and didn't skyrocket the annual maintenance like with the research center it went for me from 20M annually to 24,000M annually.
I don't know if it does it also for Unlimited users so i can't say its with all trainers.
Maybe have it instead of doing 1 day build for every factory. You could put your cursor over a building in a selected city and reduce its remaining time to 1 day.