Editing Stephenson's Rocket (section)

=== Driving wheels ===

Stephenson's most visible decision was to use a single pair of driving wheels, with a small carrying axle behind. This was the first [[0-2-2]] and first single driver locomotive.{{efn|Although ''[[Novelty (locomotive)|Novelty]]'' would also bring a 0-2-2 arrangement to Rainhill}}{{sfnp|Snell|1973|p=60}} The use of single drivers gave several advantages. The weight of [[coupling rods]] was avoided and the second axle could be smaller and lightweight, as it only carried a small portion of the weight. ''Rocket'' placed just over {{frac|2|1|2}}&nbsp;tons of its {{frac|4|1|2}}&nbsp;ton total weight onto its driving wheels,<ref>{{cite book|last1=Bailey|first1=Michael R.|last2=Glithero|first2=John P.|title=The Engineering and History of Rocket: A Survey Report|year=2000|publisher=[[Science Museum (London)|Science Museum]] |location=London|isbn=1-900-747-18-9|page=17}}</ref> a higher axle load than ''[[Sans Pareil]]'', even though the [[0-4-0]] was heavier overall at 5&nbsp;ton, and officially disqualified by being over the {{frac|4|1|2}}&nbsp;ton limit.{{sfnp|Snell|1973|p=60}} Early locomotive designers had been concerned that the adhesion of a locomotive's driving wheels would be inadequate, but Stephenson's past experience convinced him that this would not be a problem, particularly with the light trains of the trials contest.