Traction Engines 4 DVD including Set INSIDE STEAM If you ve ever wondered what makes the steam traction engine tick, then this DVD explains it all. Traction engines in all of their forms, can be seen at any of the hundreds of steam rallies held across the country every summer which honour their role in our past, and celebrate their preservation. The most recognisable form the steam road roller, is joined by other examples such as the ploughing engine, the portable engine and more, that were all built in Britains great Industrial Age for a special purpose such as ploughing or to provide the power for travelling fairground rides.