A 1:87 shelf does not need three similar excavators to look complete. A coal shovel, road-rail machine and wheel loader can give separate areas distinct purposes. These choices share a scale, not a comparable real-world size or task.
The large coal shovel belongs at the center of a mining scene. The railway machine needs track context. A loader can provide an ordinary yard activity between larger features. Keep the purpose of each area clear rather than arranging every machine in a row.
