A 3 m aluminum pole is kept at a residential site for construction
purposes at 25°C. At night, the temperature of the surroundings drops
to 2°C. What is the final length of the aluminum pole? Given the thermal
coefficient of aluminum als 23 10 °C

Modern high speed trains do not have perpendicular expansion gaps where rails are joined end-to-end any more they are mostly welded together but what might happen if there was a spell of particularly hot weather that causes inspection of the tracks?