Thousands of anti-nuclear demonstrators were trying Saturday to obstruct a tightly guarded convoy of spent nuclear fuel on its way to a German waste dump, DPA reported. Near the warehouse in Gorleben in the northern German countryside where many tons of radioactive waste are stored, some 14,500 demonstrators attended a protest rally accompanied by bands, police said. In the south of Germany, other protesters invaded railway tracks expected to be used by the freight train convoy when it arrived from a French waste-reprocessing plant at La Hague on the Atlantic coast. Two men and a woman chained themselves to the rail track at the small border town of Berg, blocking the line for hours. They had their hands attached to concrete block under the railway. Local news reports said the train was waiting at Lauterbourg on the French side of the border. The anti-nuclear movement seeks the immediate closure of all nuclear power stations and believes that waste transport and storage is unsafe. Police said they expected picketers to try forcibly to block the convoy route through Germany. Germany is studying whether to use an old salt mine near the warehouse in Gorleben as long-term storage for the waste, which originated in German power stations. The issue has become controversial after revelations that another salt mine dump, near Wolfenbuettel, has developed leaks and cracks. The convoy Saturday, carrying 17 tons of waste encapsulated in 100 tons of glass, was the 11th over the years to carry spent waste to the small town. Each shipment has faced fierce demonstrations. More than 16,000 German police were detailed to protect the convoy. Sabotage attacks disrupted high-speed passenger rail services Saturday in both France and Germany. There were no claims of responsibility, but similar attacks have coincided with waste shipments in the past. Police in Germany said they could not rule out a link between three fires in signalling equipment on the high-speed line between Hamburg and Berlin and the protests, but there were no clues as to who the attackers had been. German bullet trains had to be diverted to another route.