Many of the drawings originally used at Doncaster Works for the A1 Peppercorn class had been preserved at the NRM, and a team of volunteers spent three days collating these in the autumn of 1991. The original drawings were India ink drawings on linen; these had to be scanned into a Computer Aided Design (CAD) software program, as the microfilm NRM copies were not suitable for manufacturing purposes, and direct dyeline copies could not be made. About 95 percent of the original drawings were found, with 1,100 scanned by 1993, and a further 140 in 2001. A few poor-quality originals required re-drawing.