Niclas Füllkrug arrived early at the Adidas campus just outside Herzogenaurach, a picture-postcard town in Bavaria that was to host the German national team before this summer’s European soccer championships. The staff had been told that players would start arriving on a Monday morning, a few days before their opening game. But Füllkrug, one of the team’s forwards, turned up on Sunday night.

He had decided to make the 300-mile journey from his home in Hanover by high-speed train on Germany’s national railway carrier, Deutsche Bahn. The company was not just one of the tournament’s sponsors; it was also supposed to be a standard-bearer of the event’s ecological credentials.

But years of failure to invest in rolling stock, upgrade railways and digitalize signal boxes have made Deutsche Bahn notorious for delays and cancellations. In a country that has long prided itself on its efficiency and punctuality, Germans — as well as fans — had been warning for months that the problems might mar the tournament.

So Füllkrug was hardly surprised when he found himself crammed into a train car packed with high school students on a class trip. He spent the journey fielding their questions about life with the national team.

By the time he made it to Herzogenaurach, he had been traveling for several hours longer than expected, hardly ideal preparation for an elite athlete on the eve of a major tournament. Still, the delays had at least vindicated his decision to build in extra time. In Germany, as Füllkrug said, it pays to “have a bit of respect for Deutsche Bahn.”

Many of the hundreds of thousands of fans from across Europe — as well as a remarkable number from the United States — who have joined him in Germany will, after an often fraught opening week, doubtless understand what he means.

Deutsche Bahn had been a centerpiece of Germany’s plans for the tournament. The company offered discounted prices on “climate-friendly train travel,” part of what organizers boasted would be the “most sustainable” edition of the European Championship. When the draw for the tournament was made in December, the stage decorations included miniature versions of Deutsche Bahn’s long-distance, high-speed trains.

Yet as fans have flooded into Germany to follow their teams, the country’s rail networks have creaked. Even before the tournament started on June 14, staff members from the Munich transport authority had been dispatched to hand out ice pops to overheated travelers stuck for hours on stalled trains around the city.

In Gelsenkirchen, an industrial city in the Ruhr valley, some England fans worried about missing their team’s kickoff decided to make the three-mile walk to the city’s stadium after trams ground to a halt. In Stuttgart, Hungarian fans arriving at the city’s main train station for a game on Thursday found that, thanks to a major renovation project — begun in 2010 — it had been replaced by a giant hole.

Instead of arriving via a vast hall, alighting passengers have instead been shunted through huge wooden tunnels that snake toward the city. “I’m here to orient them,” said a representative from the Hungarian consulate, who was among the dozen or so officials dispatched to orient arriving passengers but not willing to have their names attached to the effort.

Despite their best efforts, some fans found the tunnels so long and disorientating that, even when they had nearly navigated them, they turned back and retraced their steps in hopes of getting out of the train station faster. (Deutsche Bahn recently announced that completion of the project in Stuttgart had been delayed, again, until December 2026.)

In Hamburg, Cologne and Düsseldorf, local transportation has held up a little better: After Hungary’s game against Switzerland in Cologne on June 15, trams were lined up outside the stadium to clear the backlog as quickly as possible.

Long-distance trains — offered to fans at a reduced rate — have been equally unpredictable. Germany’s rail network covers over 20,000 miles. But roughly half that length of track has been torn up in the past 70 years, leaving existing routes overloaded as demand for both cargo and passenger transportation has increased.

Late arrivals of one train have a knock-on effect for others, leading to widespread delays across the entire system. Only 63 percent of the system’s trains reached their destination on time last month, according to Deutsche Bahn. That compares with more than 94 percent punctuality in neighboring Austria and 87 percent in France.

The situation has been a cause of such acute embarrassment for Germany that Felix Dachsel, a columnist for Der Spiegel, one of the country’s biggest media outlets, felt the need last week to “apologize in all 21 languages of the tournament” for the state of the rail service. (He is taking it in good humor, at least: After all, he said, what could be more environmentally friendly than a train that did not run?)

“You can beat Germany,” he wrote, “but you will lose to Deutsche Bahn.”

Critics blame a lack of investment in the system in the decades since Deutsche Bahn was formed as a private company in 1994, fusing the state railways of the former East and West Germany. The German government is its sole shareholder.

“It has long been strategically clear that there is a lack of money,” said Andreas Knie, a professor at the Berlin Social Science Center whose research covers transit and technology. “The sums that should have been invested in the railroads, as a rule of thumb, should have been twice as high as what was actually invested.”

For a while, the system held. When Germany last hosted a major tournament, the 2006 men’s World Cup, Deutsche Bahn’s slick service was heralded as a key ingredient in the event’s success, helping to foster an enduring image of Germany as a smoothly running, thoroughly modern nation.

This time, plenty of fans — as well as Füllkrug — have learned to treat timetables as more of a guideline. That was no help for Austria fans trying to reach Düsseldorf last Monday to see their team kick off against France. Dozens were stranded just after crossing the border into Germany, with some not reaching the game until well into the second half.

Deutsche Bahn has said it will personally apologize to those left stranded. “We ask the fans to get in touch with us,” said Ralph Thieme, who is responsible for Deutsche Bahn stations that serve passengers. “We will find a good and fair way to compensate them.”

The problems have reached such proportions that, despite a government spending freeze, Germany has earmarked 40 billion euros, or $42.7 billion, to invest in its aging railway. Starting this year, work is set to begin on 40 key corridors.

Deutsche Bahn has already warned that it will mean dozens of construction sites on major routes, and with them, even more delays. Still, at least the fans do not need to worry. Work is not scheduled to begin until July 15 — the day after the final.

Tariq Panja and Christopher F. Schuetze contributed reporting.