Derails are probably one of the most interesting operating detail to add to tracks. Not only they look good but they do indeed makes operation more interesting by creating a track hierarchy. Indeed you can no longer roam freely the rails as if nothing really mattered. Some point of access are controlled and no longer the siding can be considered like a defacto extra mainline track.
In our case, we used GLX 3D printed parts. While very nice out of the bag, these details require a lot of work before working correctly. This is mainly due to various dimensional discrepancies, including how the derail itself doesn't clear the rail trucks when opened (requiring carving the 3D printed ties). Another problem is the ties are quite short and looks a little bit out of place when used with standard code 83 flex track. While not a bad product, I would hardly consider it a drop in detail and can't recommend it except if you are ready to invest a few hours making them working well. If you succeed, then they are indeed beautiful and works like the prototype. I hope GLX will improve its design in the future because this is definitely a neat detail on a layout.
From the scenic point of view, I painted the detail in faded yellow. While generally I favour acrylics, this time I used enamels due to their higher resistance to abrasion. These are working details that will be handled a lot, so better use more resistant paint. I mixed flat white and flat yellow to get a sun-faded look typical on the prototype. Later, when weathering the rails, a light wash will be applied to make the details pop and add a touch of grease and rust.