Den, I was finally able to open the page. Assuming that the blue pins are the ready tracks, white is a run-around track, yellow is outbound from the tt and green is inbound to the tt, it looks workable for a small facility. You still need to add a fueling rack, water source. The only difficulty appears to be short to no space to pull the locomotives from the run around onto the ready tracks. All the area is turnouts. This assumes that you are connecting to the main at the edge of the pictures. If the track parallels the main then you would have the distance to access the ready tracks in either directions. Ideally you would have at least one locomotive length of track with no turnouts to reverse direction. But we all know space is limited on models and we need to make compromises.
If you move the sanding, fuel and water facilities beside the run-around or put them in a position that either the run around or outbound track can be serviced, I think this answers some of Christian's concerns. It would allow you to service diesels without taking them to the roundhouse. The roundhouse then becomes a facility for repairs and required FRA inspections as they are used in the diesel era.
