German tram services disrupted as heat melts asphalt sealant

Tram services in several German cities have been suspended after continuous high temperatures caused sealant beneath the tracks to melt and clump.

The Leipzig City Transport Authority (LVB) announced the suspension of tram services until 3:30 a.m. on 29/6, citing continuous hot weather affecting operational safety.

According to LVB, high temperatures caused the sealant in the expansion joints of asphalt and concrete surfaces to melt. This sticky substance then adhered to points and tracks, jeopardizing the safe movement of trams throughout the city.

The sealant is a specialized, highly elastic material, typically an asphalt base combined with rubber, silicone, or polyurethane. It is injected into cracks and expansion joints along tram tracks to prevent rainwater, dirt, and chemicals from penetrating the underlying roadbed.

This sealant is designed to expand and contract with concrete and asphalt blocks, protecting the track structure from cracks. However, prolonged intense sunlight and the pressure from moving trams can cause the material to lose its durability, becoming soft, sticky, and dislodging from its original position.

Sealant between the tram track and road surface melted by heat in Leipzig on 28/6. *Photo: DPA*

In Leipzig, the melted sealant overflowed into the track grooves, forming clumps at numerous points across the network and threatening operational safety. LVB mobilized its entire staff to bring 50 tram sets to the workshop to clean the asphalt from their undercarriages.

All tram lines in the city, located in the state of Sachsen, were affected. The bus system, however, continued to operate as scheduled.

A similar situation was reported in Nuremberg, Bavaria. The city's transport authority stated that high temperatures softened the road surface, making tram operation unsafe. Replacement bus routes were arranged during the tram service suspension.

On 28/6, the German Meteorological Agency (DWD) recorded a new record high temperature of 41,7 degrees C for the third consecutive day, as many Western European countries experienced an unprecedented heatwave.

LVB company staff cleaning asphalt stuck to a tram's undercarriage. *Photo: LZ*

Melted sealant overflowing onto the tram track surface. *Photo: DPA*

Asphalt adhering along the length of the tram track. *Photo: DPA*

The highest temperature was recorded in the town of Neissemunde, Brandenburg. Previously, Sachsen-Anhalt recorded 41,5 degrees C on 27/6, with Bad Muskau, Sachsen, also experiencing similar temperatures.

Scientists attribute the recent Western European heatwave to a weather pattern known as an "Omega block." This pattern involves a large high-pressure area situated between two low-pressure systems, effectively trapping hot air from the Sahara Desert. This creates a scorching heat dome that affected many European nations for several days.

On 28/6, World Health Organization (WHO) Director-General Tedros Adhanom Ghebreyesus warned that Europe is the fastest-warming continent on Earth, heating up twice as fast as the global average.

"Currently, approximately 150 million people are living in extreme heat. Hundreds of deaths have occurred, schools have closed, and power grids are overloaded", Mr. Ghebreyesus stated. WHO recorded over 1.300 "excess" deaths across Europe potentially linked to the unusually high temperatures.