The 30-hour strike of German train drivers’ union GDL ended on Friday, after causing some disruption to commuter and regional services.

It affected major cities from Germany like Berlin, Munich, Hamburg and the Rhineland. According to rail operator Deutsche Bahn (DB) 18,000 trains did not run because of the strike.

The demands of the Union refer to a raise of salary by 31 percent and a separate deal from the one with DB. They warned with new strikes for the week to come if by 3 pm (0200 GMT) on Monday the DB doesn’t come with an improved offer.

According to the union, German train drivers are underpaid in comparison to drivers in other countries. Due to the strike severe congestions occurred in the major cities as commuters turned to their cars.

The train drivers returned to work Friday at 8 am (0600 GMT). Services are not to return fully to normal until Saturday, according to a spokesman of the rail company.

The estimated cost of the strike supported by DB is at 10 million euros a day (14 million dollars). This was the longest strike and the fourth one in little over two weeks. Fifty percent of commuter and regional trains did not run affecting 2.7 million travelers.

A union spokesman said that the strike was a success.

GDL has most of its members in the eastern part of Germany, and that is where the strike hit the most. The union is not so well organized in the southern region, thus the strike was not that bad in those parts.

DB is Europe’s biggest rail operator, carrying more than 5 million passengers daily. By 2009 the government tends to partly privatize it. The weekly report published by the German institute for economic research says that the wages of DB train drivers are slightly above average with the ones in similar sectors and higher than the truck drivers payment.