[Anchor]

As extreme heatwaves continue, safety alerts have been issued for railways and roads. Because rails and concrete roads expand under high temperatures and can lead to major accidents, authorities are taking all-out response measures.

Reporter Baegun has the details.

[Reporter]

A high-speed train runs on the tracks in the middle of the day.

Viewed through a thermal imaging camera, the tracks appear in dark red.

This is due to the heated rails and ballast.

On the ground, inspections are in full swing to check whether the gaps between the rails are consistent and if they are properly secured.

When heatwaves persist, expansive forces build up in steel rails, and if the fixing devices become loose at this time, a buckling phenomenon can occur where the rails warp sideways.

Because of this, automatic sprinkler systems are activated to spray water when the rail temperature rises above 48°C (118°F).

These automatic sprinklers have been added to 142 locations this year alone, operating at 599 locations nationwide.

[Han Dong-yol / Head of Osong Infrastructure Office, Korea Railroad Corporation: The (rail temperature) drops by about 5 to 10 degrees, and in places with severe direct sunlight, water is sprayed for 10 minutes about 10 times a day.]

Even so, if the rail temperature rises, trains slow down to 230 km/h or less when temperatures exceed 55°C (131°F), to 70 km/h or less above 60°C (140°F), and operations are suspended starting at 64°C (147°F).

Concrete paved on highways also expands when heatwaves persist for a long time.

Therefore, gaps called expansion joints are created between the concrete to secure space.

If these gaps become blocked or narrowed and there is insufficient space for expansion, a phenomenon can occur where the concrete slabs push against each other and heave upward.

In the summer of 2018, eight pavement heaving incidents occurred, leading to actual accidents.

The Korea Expressway Corporation has installed stress-relief joints in vulnerable sections and deployed dedicated vehicles to monitor roads.

[Ryu Sung-woo / Senior Researcher, Korea Expressway Corporation: (Stress-relief joints) provide an additional 100 mm of space in sections where clearance has disappeared. We use equipment that can automatically investigate joint constriction to detect hazardous sections in advance.]

In addition, authorities are contemplating countermeasures against increasingly extreme heatwaves every year, such as introducing construction methods that suppress concrete expansion from the initial construction stage.

(Video reporting: Kang Si-woo | Video editing: Shin Se-eun | Design: Choi Ha-neul)