I built this model just for fun from plans available on http://www.john-tom.com/html/SteamPlans.html
. The model is a vintage Case tractor manufactured circa 1800's that has a wood fired boiler and steam engine. It is fascinating to me that some originals are still around in fully operating condition as well as many miniatures created by hobbyists which you can find on the InterWeb.
The assembly, with the exception of the gears, was created in one file primarily using the PartDesign workbench. The gears were created in a separate file and imported last as .STEP files. Trying to work on the gears in the master file slowed FreeCAD to an unbearable crawl even with an I7 Quad Core CPU.
Most of the parts were fairly straight forward to model except perhaps for the worm-gear drive steering assembly that includes crossed chains to turn the front axle. The boiler with the three(3) condensate return tubes was also quite a challenge to create strictly with PartDesign but possible. All of the fasteners are not included but a few of the rivets were modeled for visual effect only. File size is about 31 Mb for the assembly and 21 Mb for the gears both of which I can post on DropBox if anyone is interested in more detail.OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.16.6706 (Git)
Build type: Release
Python version: 2.7.8
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 6.8.0.oce-0.17