For when you have a bunch of trains and want to group them. Train schedule, interrupts and wagon layout (configurable) of all currently ungrouped trains are checked against the reference train and added to its group if they match. Schedule comparison ignores temporary stops and tries to change conditions and stop order in ways that preserve their behaviour in order to increase sensitivity (a AND b ≡ b AND a, A -> B -> C ≡ B -> C -> A ≡ C -> A -> B, a < b ≡ b > a). Also copies colors from the reference if desired.