Placing a ghost of a rail signal over an existing rail chain signal, or, vice versa, a ghost of a rail chain signal over an existing rail signal, causes the error sound ("durrp-durrp") to play. The error sound is overlayed above the sound that placing ghosts usuallay plays.
Expected behaviour: No error sound, only ghosting sound is played, as ghosting rail signals over each other to swap their type is a valid, functioning action.
