lengths of railway tracks have small gaps between them. Why are the tracks built this way and what might happen it there were no gaps?

The gaps allow the tracks to expand. If there were no gaps, the rails would run into each other as they expanded and would be raised up or bent.

Railway tracks are built with small gaps between them for a specific reason - to allow for expansion and contraction of the metal rails due to changes in temperature. This design feature is known as "rail expansion joints" or "rail joints."

When temperature changes occur, metal expands or contracts. In the case of railway tracks, exposure to sunlight, weather conditions, and even passing trains cause the tracks to heat up or cool down. If the tracks were built without any gaps, the metal would have no room to expand when heated. This expansion could cause various issues, ranging from bending and warping to the buckling of the tracks.

To prevent these issues, gaps are intentionally placed between the tracks at regular intervals. These gaps provide space for the metal to expand lengthwise without causing significant deformations or damaging the track structure. The size and spacing of these gaps are carefully calculated based on factors such as the type of rail, expected temperature variations, and the materials used in the track construction.

If there were no gaps between the tracks, several consequences could arise:

1. Buckling: Without room for expansion, the rails would buckle and curve as they are heated. This can lead to severe deformations and derailments.

2. Stress and fractures: Excessive stress due to thermal expansion could cause the rails to develop fractures or cracks, compromising the track's integrity and safety.

3. Misalignment: Unequal expansion of adjacent rails could result in misalignment. This misalignment could affect train stability and increase the risk of accidents.

4. Restriction of movement: Fixing the tracks rigidly without gaps would restrict the natural movement of the rails, resulting in increased wear and tear and reduced lifespan of the tracks.

By incorporating small gaps between railway tracks, engineers allow for the necessary expansion and contraction of the metal, which helps maintain the integrity, stability, and safety of the entire railway system.