VIENNA (Reuters) - The Austrian capital turned a distinct shade of red on Friday when thousands of Turks and Croats converged on Vienna for their Euro 2008 quarter-final.

The unmistakable chequered strip of Croatia, with its red and white squares, could be seen in almost every square and bar in the city while a few crimson-clad Turkey fans were also making themselves heard.

Some 200,000 fans are due in the city which has about 1.68 million residents with about 4,600 police on duty, supported by 15 Croatian and four Turkish hooligan spotters.

However, large-scale trouble is not expected given Vienna has sizeable Turkish and Croatian communities.

"Whoever wins we will have a long night and I am sure victorious fans will want to party in the city after the game," said Christian Stella, a spokesman for Vienna police.

The championship has already produced some cracking games and the partying fans could be in for another treat if Turkey and Croatia stick to their attacking instincts.

The winning team will face Germany in the semi-finals in Basel next Wednesday after Joachim Loew's side beat Portugal 3-2 in a thrilling first quarter-final on Thursday.

While the Germans were raving about midfielder Bastian Schweinsteiger or "Schweini" for his match-winning performance, the Portuguese were heading home with their heads held high after impressing everyone with their dynamic play.

Around 500 Portuguese fans, the majority expatriates living in Switzerland, gave the squad a rousing farewell at their Neuchatel hotel.

NEVER FORGET

The Dutch, who face Russia in the third quarter-final in Basel on Saturday, have also left their mark on Switzerland's capital, Berne.

Their army of fans which flooded the city for their three group matches created a sea of orange which the reserved locals will never forget.

The city mayor therefore wants to give Netherlands some of the Stade de Suisse turf as a gesture of thanks for the fantastic atmosphere they generated.

The turf is being replaced by the stadium's normal artificial surface and the mayor said he would be happy for the divided-up grass to go to Dutch fans, the coach or the national federation -- whoever wanted it as a keepsake.

There would be no cost, he said.

There has been one downside to the tangerine surge, though.

Switzerland's national railway has told its workers to stop using their normal orange reflective vests after confused Dutch soccer fans started following them on to the tracks.

"We have now given out yellow vests to all our staff who have to work on or cross the tracks in Basel, where the Dutch fans are now based," railway spokesman Oliver Tamas said.

"It has raised a few eyebrows but we think it's a necessary measure to ensure the safety of our guests."

Spain coach Luis Aragones and fullback Sergio Ramos also raised eyebrows after a heated discussion took place during training ahead of Sunday's last quarter-final with Italy.

The coach later played it down. "He expressed his opinion, that's all," Aragones, who similarly is known for not withholding his thoughts, told reporters.

(Additional reporting by Iain Rogers, Alex Hudson, Mark Ledsom, Simon Baskett, Rex Gowar)