"I was creeping up slowly and as I went on it, it just had a horrible sinking feeling."
He said he was extremely lucky to have survived the accident unharmed.
"It's one more of my nine lives," he said.
Ross Lawrence was driving his tractor in a paddock about 50m away from the bridge. He was carting the maize in his tractor to and from the trucks.
"I was just up there and saw the driver's window smash and the front sort of fell down," he said.
"I just hoped it wasn't his head that broke the window.
"I just ran up and yelled at him to make sure he was alright, and then he got out real carefully along the side of the bridge," he said.
"It was a bit of excitment for the day."
The truck was eventually lifted from the bridge by a crane about 2.30pm.