A method of cleaning encrusted ballast comprises the steps of screening the encrusted ballast to separate detritus from the ballast, washing the screened ballast with water while removing the separated detritus on a conveyor belt unit, clarifying the washing water to produce a clarified water portion and washing water sludge, and disposing of the washing water sludge by moving it to the detritus on the conveyor belt unit for common removal with the detritus.