Denmark’s rail network is dangerously vulnerable, warns transport expert

Denmark’s railway system lacks resilience against unexpected disruptions, a leading transport researcher told national broadcaster DR after a fallen overhead power line halted cross-country services on Sunday.

Steven Seth Harrod, an associate professor at the Technical University of Denmark (DTU), called the system “truly vulnerable,” citing the chaos that followed when a power line collapse near Sorø severed the main rail link between Zealand and Funen. With no backup plan, authorities defaulted to replacement bus services—a solution Harrod dismissed as unsustainable.

“When there’s a breakdown, Plan A is always bus replacements,” he said. “There is no Plan B for keeping trains running.”

Harrod proposed three measures to strengthen the network’s robustness.

Build redundant routes

Denmark’s geography leaves little room for alternative rail paths, but Harrod pointed to incremental progress. The existing high-speed line between Copenhagen and Ringsted effectively creates a second route on that segment, while a proposed high-speed link on western Funen would add redundancy there. He also urged planners to include rail capacity in any future Kattegat fixed crossing to Jutland, providing a backup to the current Great Belt route.

“If you travel from Hamburg to Munich, you can go via Frankfurt or Berlin,” he said. “We don’t have those options, so any disruption puts immense pressure on the entire system.”

Maintain diesel locomotives for emergencies

With five to seven overhead line failures occurring annually, Harrod argued for a fleet of diesel locomotives as a stopgap. These could operate on affected stretches—such as Sunday’s outage between Slagelse and Ringsted—without relying on electric power.

“DSB [Danish State Railways] has phased out diesels to meet zero-emission targets by 2030, but they’d be ideal as backups,” he said. “The cost is justified when you consider the alternative is total paralysis.”

Invest in battery-powered trains

Harrod highlighted battery-electric trains as a third option, capable of covering short distances when overhead lines fail. While Denmark’s current procurement focuses on non-battery electric units for the next 20 years, he questioned the wisdom of eliminating all redundancy.

“What happens in a war, a terrorist attack, or sabotage?” he asked. “How do we keep trains moving on sections without power?”

The researcher acknowledged the system’s growing complexity—digital signaling, computer-controlled operations, and high-speed units—but warned that a single failure now risks cascading delays. Sunday’s incident, which stranded passengers until 6 a.m. Monday, underscored the urgency of his proposals.