Rodger and others,
Building east of CHS is State Archives. I remember using east door entry and being sent down one or two levels to the State Archives Library. You can see microfilm of some of the years of Governor's REPORT on Equalization of railroad valuation (for taxation). Some years may not have been filmed so you need to call up the boxes of the book form reply by the railroads.
There was a charge for out of state visitors but you should see them free. Maybe you can call and have it ready in advance for the years you want.
They were very helpful and have much railroad data to offer.