Germany faced delays and cancellations in the early morning rush hour as rail workers stopped work.
The German Transnet and GDBA unions are in dispute about pay and working conditions at the national rail operator Deutsche Bahn.
The unions want a 10% wage increase and improved working hours including at least 12 free weekends per year.
Nine cities are affected by the stoppage, which follows a company pay increase offer the unions say is worth only 1% this year and next.
The company claims it is worth 2.7-3.0%.
Worst hit were trains in the southern state of Bavaria where there were numerous cancellations and lengthy delays.
Deutsche Bahn said it was bringing in extra staff.
German unemployment now 7.8%
German unemployment rose by 56,000 in January, its third monthly increase in a row, and the biggest rise in nearly four years.
The rise took the adjusted jobless total to 3.267m, giving an unemployment rate of 7.8%.
The headline unadjusted jobless total rose by 387,000 to 3.489m.
The German jobless rise poses risks to Chancellor Angela Merkel's conservatives and her coalition partners, the Social Democrats, who will contest a federal election in September.