The “Onward” was an unconventional prototype locomotive built by the Hinkley Locomotive Works for the Swinerton Locomotive Driving Wheel Company. It was delivered in 1887 and carried the works number 1739 and had been ordered by C. E. Swinerton who wanted to increase the adhesion of the driving wheels. Not knowing that even steel tires are deforming under the weight of a locomotive, he thought that round wheels do only make contact with the rails in one point. So his conclusion was that the contact area could be increased by the use of wheels with polygonal tires.

The tires of the drivers consisted of 118 faces with a length of roughly two inches each. To demonstrate the increase in adhesion, the locomotive was built as a 4-2-2 with only on set of drivers. With some potential customers which believed that this concept might work, the locomotive was tested on several lines in the North East of the USA. No orders followed, and it can be assumed that there were strong vibrations. Now the locomotive was equipped with round wheels and sold to the Portland & Rochester Railroad. Later they brought it to the Manchester Locomotive Works to rebuild it into a conventional 4-4-0. It became Boston & Maine class A No. 598 in 1900 and was scrapped in September 1905.