The drivers are spoked. Note that the roof is curved instead of peaked as in the drawing. The pipes above the roof could be for a steam condensing apparatus, but there is no mention of it in the text.
http://1stclass.mylargescale.com/SteveShyvers\Steam Traction\UFRR Tram Photo.jpg
http://1stclass.mylargescale.com/SteveShyvers\Steam Traction\040 Tram Diag.jpg
Steve