I found this image while looking for "Traction Engines".

I found this image while looking for "Traction Engines". My first reaction - influenced by this (https://upload.wikimedia.org/wikipedia/commons/9/95/Winsor_McCay_1920-10-03_Wheels_and_Cogs.JPG) Winsor McCay drawing - was "How big is the clock?!"
http://www.wisconsinhistory.org/Content.aspx?dsNav=Ro%3A60%2CNrc%3Aid-5%2CN%3A4294963828-4294955414&dsNavOnly=N%3A1135&dsRecordDetails=R%3AIM50787#.V4Ne0O5oCgU.google_plusone_share