Traction engines tend to be large, robust and powerful, but heavy, slow, and have poor manoeuvrability. Nevertheless they revolutionised agriculture and road haulage at a time when the only alternative prime mover was the draught horse. Here is a typical steam traction engine. 1910 Allchin 7 nhp agricultural engine "Evedon Lad", at Stoke Goldington steam rally in 2005.