Tangent track:
In a tangent track, the rails are straight and aligned parallel to each other. The train travels in a straight line without any curves. As a result, the wear of rails is relatively low in this section. The wheels of the train exert uniform pressure on the rails, leading to even wear.

Sharp curve:
In a sharp curve, the rails are curved, and the train has to negotiate the curve by changing its direction. This requires the wheels to exert lateral forces on the rails, leading to increased wear. The outer rail of the curve experiences more wear compared to the inner rail due to the centrifugal force acting on the train.

Tunnels:
In tunnels, the wear of rails is not necessarily higher compared to other sections. However, tunnels may have specific conditions that can contribute to rail wear. For example, tunnels are often subjected to moisture and water seepage, which can accelerate corrosion and wear of the rails. Additionally, the confined space and lack of ventilation in tunnels can lead to higher temperatures, causing thermal expansion and contraction of the rails, leading to increased wear over time.

Coastal area:
In coastal areas, the wear of rails can be influenced by several factors. The presence of saltwater and salt-laden air can accelerate corrosion of the rails, leading to increased wear. The coastal environment is also prone to high humidity and moisture, which can further contribute to the corrosion process. Additionally, coastal areas may be exposed to harsh weather conditions such as strong winds and storms, which can lead to increased wear and damage to the rails.

Conclusion:
Among the given options, the wear of rails is maximum in sharp curves. The lateral forces exerted on the rails during the negotiation of curves result in uneven wear, with the outer rail experiencing more wear compared to the inner rail. It is important to monitor and maintain the rails in curves to ensure safe and efficient train operations. Regular inspections, lubrication, and proper maintenance practices can help minimize rail wear in these sections.