When the bridge was built in 1846, it was built in a hurry so that the Wymondham to Dereham railway line could be opened.
On inspection it was discovered that it was structurally unsafe, which meant that the line opening couldn't go ahead.
It was decided to rebuild the unsafe part of the bridge and to hurry things along work was ongoing for 24 hours a day.
There being no lights to work by, fires were lit on the bridge at night. When they started to demolish the part that was to be rebuilt,
the whole bridge collapsed and all the workers underneath were covered in rubble, and the fires.
No one was killed fortunately, but many were injured and burnt.
So the whole bridge had to be built again.