The dump truck was delivering ballast for engineering works adjacent to the tracks along a railway access road but had not lowered his rear tipping body.
Leicester Crown Court heard that this came into contact with the wrought iron pedestrian knocking it off its pillars and onto the tracks, by high street in Barrow on Soar village centre.
The alarm was raised but too late to prevent the East Midlands Trains service was travelling at 65mph being derailed at Barrow on Soar in Leicestershire in February 2008.
“Network Rail’s poor planning and management of construction site safety at Barrow placed members of the travelling public a risk,” Darren Anderson of the Office of Rail Regulation said.
Leicester Crown Court heard the firm did not have a proper construction site safety assessment in place.
A train driver had to be cut free from his cab after the bridge collapsed in the accident, but no-one else was hurt.
The train driver was trapped for two-and-a-half hours and suffered serious leg injuries.
Network Rail was also ordered to pay costs of £32,000