had proved that steam locomotives could perform such duties. Robert Stephenson and Company was the pre-eminent builder of steam locomotives in the first decades of steam for railways in the United Kingdom, the United States, and much of Europe.

Towards the end of the steam era, a longstanding British emphasis on speed culminated in a record, still unbroken, of 126 mph by LNER Class A4 4468 ''Mallard''; however, there are long-standing claims that the Pennsylvania Railroad class S1