German train drivers are set to strike at the end of the week after negotiations about a wage agreement collapsed, the GDL union said.
Officials say a prolonged dispute would hurt the economy
The strike will affect passenger and freight trains for a limited period from Friday, GDL added.
National rail operator Deutsche Bahn had proposed a 10% salary increase, but GDL is holding out for a 30% rise.
Deutsche Bahn has been locked in a wage dispute for months with GDL, which says that train drivers are underpaid.
The rail operator has already agreed a smaller deal with two other unions which will see workers receive a 4.5% rise in wages.
GDL chairman Manfred Schell said that Deutsche Bahn "bears sole responsibility" for the strike.
Government officials have warned that a prolonged strike could damage the German economy.
Deutsche Bahn carries some 5 million passengers daily.