Snow is cleared from the southern runway at Heathrow airport in west London Dec 21, 2010. Snow and freezing temperatures continued to ground flights to and from Britain on Tuesday, with travellers hoping to get away for Christmas likely to suffer delays and cancellations for several more days. [Photo/Agencies]

LONDON- Airline and international train services were limping back towards normal in parts of Europe on Wednesday, but the lingering effects of ice and snow that caused widespread chaos still weighed on schedules.

Related readings: Snow snarls traffic in London  Heavy snow disrupts travel across N Europe  Heavy snow hits air travel, roads in Europe

The disruptions to airlines and high-speed trains in continental Europe, and linking Britain to the continent, created travel chaos for tens of thousands of travellers in the busy Christmas period following heavy weekend snowfalls.

They also brought calls for legislation to force airports to deal more effectively with snow and other bad weather.

European Union transport chief Siim Kallas said he was considering forcing airports to provide a minimum level of infrastructure support during severe weather.

London's Heathrow, the world's busiest international airport, and Frankfurt Airport, the biggest on the continent, said on their websites that operations were returning to normal after severe disruptions.

Wolfgang Prock-Schauer, chief executive of airline BMI, owned by Lufthansa, accused BAA of being unprepared for the heavy snow at Heathrow.

"What is really incredible is that 10 cm (4 ins) of snow closed the airport down for two days and then it operated at one-third capacity," he told the Times newspaper.

"BAA was not prepared. It did not have enough de-icing fluid."

A spokesman for BAA, which is owned by Spain's Ferrovial, denied there had been a de-icer issue at Heathrow and said lessons would be learnt.

But he added: "This was unprecedented weather which closed most of northern Europe's airports."

Heathrow was scheduled to operate 70 percent of a normal day's service, about 800 flights, but it was still advising passengers not to come to Heathrow unless they had confirmed flights, the spokesman said.

"We're hoping by the end of the day we'll be up to full operation," he said.

Heathrow reopened its second runway on Tuesday, offering a ray of hope for thousands of passengers stranded in departure halls, some for days in scenes that British newspapers said resembled refugee camps.

"Airlines are currently operating a significantly reduced schedule while they move diverted aircraft and crew back into position," BAA said on its website.

British Airways said that, in line with a directive from BAA, it would operate only a third of its normal flight schedule at Heathrow until 6 am on Thursday.

"It will take some time to rebuild an operation of our size and complexity at our hub airport, Heathrow," the airline said on its website.

"We ask you not to travel to the airport unless you have a confirmed booking on one of the flights that is operating."