In which country the first railway line was laid?

The first railway line was laid in England. The Stockton and Darlington Railway (S&DR) which opened in 1825, was 40 km long and was built between Witton Park and Stockton-on-Tees via Darlington and to several collieries near Shildon in north-eastern England. It was also the longest railway at the time and it was taken over by the North Eastern Railway in 1863, but by agreement continued to operate independently for a further 10 years.