Temperatures reached up to 50 degrees Celsius on an ICE train from Berlin to Cologne on July 10 after the cooling system broke down. Several passengers collapsed and nine students on a class field trip were subsequently hospitalised when they got off the train in Bielefeld.

Witnesses described dramatic scenes aboard the train, as dehydrated students reportedly stretched out in the aisles and one woman smashed a window in hopes of getting fresh air.

Until Wednesday, Deutsche Bahn had only offered the victims compensation of 1.5 times the worth of their tickets on that day. The VZVB German consumer protection agency had suggested that €300 would be an appropriate amount.

The company declined to provide more details about their new offer of €500, but Deutsche Bahn boss Rüdiger Grube, Transport Minister Peter Ramsauer and members of the parliamentary transport committee plan to meet on Thursday to discuss the situation.

Around 50 defective train air conditioning systems were reported in the days following the incident, with ICE 2 trains particularly affected. There was also criticism of Deutsche Bahn employees for the way they handled the malfunctions.

State prosecutors have also opened an investigation into the Bielefeld train conductor’s actions to find out whether he could or should have stopped the overheating train sooner.

On Wednesday, Deutsche Bahn also denied reports by broadcaster ZDF that temperatures in that train had actually reached more than 70 degrees Celsius, but added that internal analysis estimated it had risen to a scorching 61 degrees in a utility area.

“However this power unit is located outside the passenger areas on the underside of the train,“ the company said.

While Deutsche Bahn has referred to the climate control problems as a new phenomenon, Berlin daily Der Tagesspiegel reported on Wednesday that internal documents showed several such concerns already the summer of 2008.