Half Track Restoration Project
The Creeper Track Society is restoring a Citroën Kegresse P17E half-track vehicle. These fellows are carrying out the restoration in detail and documenting the process on their website: Creeper Track Society. I'm very interested in the process -- and the excellent skill and dedication of the team -- as they show their work restoring the boogies to building their own track replacement from scratch.
Notice on this image, for example, that the bogies support the rear vehicle weight. These small diameter metal wheels in the centre of the track are attached to the frame via 2 sets of pivoting lever arms, and this configuration allows for an even distribution of weight across all four wheels while maintaining excellent ground following properties. You can also see that the main drive wheel is in the front and the rear tension wheel are both off the ground. This is an effective way to isolate function (front drive, rear tension, bogies supporting) to improve efficiency and reduce stress on the track.
The downside, however, is that this design limits power handling and weight since the front drive wheel can theoretically pull the tension wheel back and create enough slack to dislodge the track from the running gear. This is why large bulldozers typically do not use this configuration.
They have a detailed page on how they built a rubber conveyor belt based track for the project. Notice it is a rubberized belted conveyor belt upon which they drilled holes and bolted on custom metal cleats and rubber centre blocks. There is an additional raised centre block inside the track to prevent derailing / de-tracking. One advantage using this continuous belt method is the simplicity, rolling efficiency, and lighter weight properties (although the steel cleats offset that a bit). The downside, as already mentioned, is lesser power handling and overall robustness as compared to full steel linkage design.
I think the work these fine men have put into the project is admirable and I appreciate the thorough documentation process for others to enjoy.