Katherine residents have detailed the dramatic scene they witnessed after a freight train collided with a truck on the outskirts of town earlier this week.
It comes as recovery works begin on the damaged rail line, which is expected to re-open by late Saturday.
Simone Siedel, manager of Phoenix Spelling Yards in the Katherine suburb of Cossack, said she heard a loud train horn followed by a crash just before 11am on Wednesday.
"When we arrived, there was a lot of thick, black smoke coming up," she said.
"It was a jumbled mess of carriages and containers that had come off."
Ms Siedel said one train crew member was suffering pain in his neck and had "quite a lot of blood coming from his head".
"We just tried to keep him still until we could see the ambulance," she said.
Jack Radke, a contract labourer working at the yards, rushed to the injured man's aid using a buggy.
"We raced him down and around underneath the railway line and back up the other side so he could get into the ambulance," he said.
NT Police, Fire and Emergency Services (NTPFES) said the train had been transporting general freight as well as a flammable diesel container.
The clock was ticking to move the injured crew members away in time, Mr Radke said.
"We just got him as far away from the flames as we could because there was a big mob of diesel that they reckon was going to explode," he said.
The diesel container caused a fire after the crash, which spread into nearby bushland before it was contained by emergency services.
All four people who were taken to Katherine hospital on Wednesday have since been discharged, rail operator Aurizon said in a statement.
Ms Siedel said she could not believe there were no fatalities after witnessing the scale of the damage.
"I think everybody in town is just grateful that nobody was killed," she said.
NT Police and the Office of the National Rail Safety Regulator (ONRSR) are investigating what caused the collision at the railway crossing.
In a statement, a spokesman from ONRSR said two senior investigators attended the scene on Wednesday to collect evidence.
"While the initial observations suggest infrastructure including signalling and level crossing equipment was functioning, as the investigation remains ongoing, it is not appropriate for ONRSR to speculate on its findings," the spokesman said.
There have been a total of four train derailments in the NT since January 2013, when ONRSR took over as the rail safety regulator.
The spokesman said none had resulted in any fatalities or serious injuries.
Recovery works on the track began on Thursday afternoon after the Office of the National Rail Safety Regulator (ONRSR) and NT Police released the crash site back to Aurizon.
In a statement, an Aurizon spokesman said those works would include the removal of damaged locomotives and wagons as well as repairs to the track.
"Aurizon currently estimates the track repairs to be completed and rail services expected to re-commence by late Saturday, pending any unforeseen issues," the spokesman said.
A detour is in place around the crash site for light vehicles only.
However, large vehicles such as those used for moving cattle or quarry materials remain blocked from road access.
Affected business owners including Ms Siedel, who was due to move 650 cattle this week to NSW and Queensland, must wait in limbo.
With the NT's key railway line under repair, major supermarkets have shifted some of their stock from rail to road.
As a result, drivers along the Stuart Highway may encounter more road trains and heavier traffic, according to NT Road Transport Association executive officer Louise Bilato.
"We ask everyone to be aware of those potentially additional trucks on the road, and to be respectful of what they're doing," she said.
Ms Bilato said freight travelling from Adelaide to Darwin would be unloaded off the train in Alice Springs and onto trucks for the remaining journey.
"After the rail network is restored, those containers will come up as they normally do on the rail," she said.