Railroad ties, also known as railway sleepers, are the rectangular supports found underneath the rail tracks of a railway system. They are commonly made of concrete, wood, or composite materials, and provide a stable base for the rails to rest on. Other terms used to describe railroad ties include railway timbers, cross-ties, track pads, track supports, and tie plates. These synonyms all refer to the same component of a railway system and are used interchangeably in the industry. Maintaining and replacing railroad ties is an important aspect of railway maintenance to ensure the safety and reliability of train transportation.