A vehicle came within seconds of being hit by a train at a crossing after a signalling error, a report revealed.
The driver of a Greater Anglia service applied the emergency brake about 350m (1148ft) from the Worlingham crossing near Beccles, Suffolk, on 8 July.
The train was doing 55mph (89km/h) and was 14 seconds from the barriers, which a signaller had allowed to be opened.
Network Rail said it had introduced measures to reduce the risk of signaller errors.
The Worlingham crossing is “user-worked”, meaning people must phone a signaller for permission to use it.
In a report, the Rail Accident Investigation Branch (RAIB) said a worker at Saxmundham signal box had authorised two vehicles to cross.
The driver of the Lowestoft to Ipswich train braked after spotting a vehicle on the tracks, and a second that was about to cross but reversed back.
The RAIB said additional information on train positions was provided on the signaller’s workstation but he had not been trained to use it.
“Had he been trained and assessed as competent, it is possible he would have chosen not to give permission for the use of the crossing,” the report said.
The investigation also found he had taken six telephone calls from other crossings in the 10 minutes before the incident.
It noted similar incidents on the route in recent years, including a collision between a train and a tractor near Thetford in 2016, which seriously injured the tractor driver.
Investigators told Network Rail in 2017 it had not assessed the workload of signallers and some had no reliable way of knowing nearby train movements.
The RAIB said management must continue “to focus on reducing the risk from signaller errors”.
Ian Bradler, from Network Rail, said: “We are committed to make level crossings as safe as possible for everyone and we take incidents like this very seriously.
“We have a plan in place to upgrade level crossings in this area to make them safer.
“We have also put measures in place to reduce the risk of signaller errors and briefed staff accordingly.”