The invention relates to a machine train composed of a road milling machine 1 that travels in front and comprises a machine frame 3 supported by crawler tracks 3, 4 or wheels and a milling drum 10 arranged on the machine frame that is for milling away material, and to a road finisher 16 that travels behind and comprises a machine frame 18 which is supported by crawler tracks 17 or wheels and on which a reservoir 19 for material to be laid and a screed 20 for laying material are arranged. The invention also relates to a method for operating a machine train composed of a road milling machine travelling in front and a road finisher travelling behind. The machine train composed of the road milling machine and the road finisher is characterized in that the road milling machine 1 has a profile data determining device 33, wherein the profile data determining device 33 is configured so that a sequence of height profile data describing the height of the road surface in the longitudinal direction is determined while th
