A railroad is a system of tracks and trains used for transporting goods and passengers over long distances. It consists of steel rails laid on wooden or concrete ties, which are supported by a bed of gravel. Trains run on these tracks, powered by locomotives that can be fueled by diesel or electricity. Railroads have played a crucial role in the development of many countries, facilitating trade and travel. They connect cities and regions, making it easier to move large quantities of freight and people quickly and efficiently. The invention of the steam engine in the 19th century revolutionized this mode of transportation.