Sheffield products were characteristically of high value in relation to their weight. This applied in traditional trades such as cutlery or files, to the early railway products, springs, buffers, tyres and axles, and to heavy but highly priced armament materials such as gun forgings and armour-plate. In such circumstances its inland location and general lack of supporting blast furnace capacity was of no material significance; skill and reputation were more than sufficient counterweights to a less than ideal material supply situation. How ever, for nearly 20 years Sheffield also played a prominent part in two fields from which it had to withdraw as prices fell and other, better located and eventually integrated, iron and steel operations at home and abroad undercut it. One was the manufacture of steel plate, both for boiler work and shipbuilding; the other, far more important, trade was in steel rails. When others withdrew wholly or in part from rail manufacture to concentrate their resources on less vulnerable lines Cammell's continued as a leading producer. It made rails in the Sheffield area for almost 70 years.

Until after the mid-nineteenth century the scope of Sheffield steel-making had been limited by the small capacity of its producing unit, the crucible. Ingenious special arrangements, involving the coordination of large numbers of workmen, permitted the pouring of numerous pots into ingots, or castings during very short periods, so that some works produced relatively massive items, such as shafting for ships, but such operations were not routine: normal size limits were far lower.