As requested more images attached. This model took around 7 weeks to draw all the parts and assemble.
This was all done on FreeCAD V0.16 mostly in Partdesign WB with the use of some primitives to construct items like valves etc.
With regards to the piping, I cheat somewhat by making the pipes in sections and assembling to the main structure, the sections of the pipe can the be adjusted to fit an positioned by circular edge constraint.
I think the most difficult parts to generate were the main drive wheels.