Rolling plant (10) comprising at least: a continuous casting device (11); a tunnel furnace (15) for maintenance/equalization and possible heating; a rolling train consisting of a roughing train comprising from 1 to 4 rolling stands (18a, 18b, 18c) and a finishing train comprising from 3 to 7 stands (21a-21e); a rapid heating unit (20), with elements able to be selectively activated, interposed between the roughing train and the finishing train. For each lay-out of the rolling line (10), the position of the rapid heating unit (20) which defines the number of stands (18a, 18b, 18c) which form the roughing train, disposed upstream of the unit (20), and the number of stands (21a-21e) which form the finishing train, disposed downstream of the unit (20), is calculated as a function of the product of the thickness and speed of the thin slab. The product is in turn a function of the hourly productivity in tons/hour desired to be obtained, and is made to work either in coil-to-coil mode, or in semi-endless mode or in endless mode. One of the three modes of the rolling process is selected according to the quality of the steel produced, to the maximum casting speed possible for the quality of steel, to the final thickness of the strip and to the production cost.