BERLIN (Reuters) - Germany's state railways will on Monday close for five months a main line connecting the financial centre of Frankfurt with the south to carry out a 1.3 billion euro ($1.4 billion) upgrade to creaking infrastructure.

WHY IT'S IMPORTANT

Tracks between Frankfurt and Mannheim are congested, and delays can have a major impact elsewhere in Germany's 33,000-kilometre (20,000-mile) network, as well as on trains to neighbouring countries like Switzerland and France.

The state of German railways has been in the international spotlight during the Euro 2024 soccer tournament, with fans complaining of crowded trains and travel disruptions.

CONTEXT

While rail operator Deutsche Bahn has bought hundreds more modern high-speed ICE trains in recent years, many tracks, signal boxes and other infrastructure need repairs or upgrades.

In June, just over half of all long-distance trains were on time, according to Deutsche Bahn statistics. In reality, more connections are affected because the company classifies a train as delayed if it is at least six minutes late. Cancelled connections are not counted.

BY THE NUMBERS

Deutsche Bahn's planned investment of 1.3 billion euros in this project is up from an initial estimate of 500 million euros.

Over the next five months, it will rebuild 140 kilometres of tracks and overhead wires, improve 20 stations and replace more than 150 switches.

WHAT'S NEXT?

Deutsche Bahn hopes disruptions on its overhauled main lines will decline by 80%. In total, the company plans to renovate 40 rail corridors to stabilise the system.

The next major renovation is scheduled for next year between Berlin and Hamburg, Germany's most populous cities.

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(Reporting by Markus Wacket and Thomas Seythal, Editing by Miranda Murray and Mark Potter)