The gang reportedly arrived at a depot in Slavkov, in the east of the country, with forged paperwork claiming that the footbridge over the disused railway track had to come down.
A Railways spokesman, Pavel Halla, said the cost of the theft was worth millions.
“The thieves said they had been hired to demolish the bridge, and remove the unwanted railway track to make way for a new cycle route,” he said.
“It was only after they had gone that checks were made and we realised we’d been had. The cost of replacing the bridge will run into millions.”
Scrap metal theft has can cost millions to the victims.
Last month The Daily Telegraph reported that metal theft had cost the Church of England £10 million last year, with the value of church insurance claims rise from £173,000 to almost £4.5 million across the country.
Metal theft is estimated to cost the British economy £770 million every year.