A train was a quarter of a second from hitting a car on a level crossing, a report has revealed.
The train was 200m from the Norwich Road crossing when the safety barriers lifted, the Rail Accident Investigation Branch (RAIB) said.
The Norwich to Sheringham passenger service was travelling at about 45mph (72kmh) when the near-miss happened at 19:43 GMT on 24 November.
Greater Anglia said it was “very sorry” for any upset caused.
In a report, the RAIB said the barriers were lowered until the Greater Anglia train was about 200 metres from the crossing.
“The barriers then lifted, the level crossing warning lights went out and cars began to cross the railway.
“The train driver applied the train’s emergency brake and sounded its warning horn, but the train was unable to stop before reaching the crossing.
“No road vehicles were struck but a car passed in front of the train around a quarter of a second before the train went over the crossing.”
The report said the level crossing equipment was installed in 2000 and used a “predictor system” to detect the speed of approaching trains and time the interval between barriers closing and trains arriving.
“Since the incident, Network Rail has modified the settings of this and similar level crossings on the line to reduce the chance of a repeat of this incident,” the RAIB said.
A further investigation will now look at the predictor system and the design of the train.
A spokeswoman for Greater Anglia said it was “fully co-operating” with the investigation.
“We agreed to run our trains at a reduced speed on the Norwich-Sheringham line while Network Rail examined all level crossings and the rails on this railway line,” she said.
“We are very sorry for any upset this incident may have caused customers and colleagues.”