Residents of Molong say it was “unbelievable” how fast water rose and rushed through the NSW town, smashing buildings before quickly receding and leaving behind destruction.

About three-quarters of the historic town was damaged when flooding ripped through overnight Sunday, leaving ‘apocalyptic’ scenes in the main street.

“It looks like a cyclone has been here. It’s a disaster zone,” said resident Peta Porter.

The immense depth and force of the water carried at least two shipping containers down the main street, lifted parked cars and knocked out the back wall of the supermarket .

The sudden weather event wiped out businesses as waters rose the height of roofs, smashed shop windows and gushed through the town’s main street.

Numerous roads were ripped up and a new hockey field destroyed. The floodwaters knocked out the back wall of the local supermarket.

Dozens of people were forced to take shelter in the RSL overnight as a deluge flooded the small rural town in central west NSW.

“It was just unbelievable how fast the water came,” Mary Mulhall said from the local RSL on Monday.

“It rose really quick and then it sort of went down fairly quickly as well but it just devastated on its way through.”

“The shop owners would be devastated because most of the shops have all gone and the supermarket’s just gone altogether.”

Apocalyptic scenes

Real estate agent Scott Petersen said the town centre looked “apocalyptic” on Monday morning.

“There were cars pushed away, every shop has had five-foot of water through it,” Mr Petersen said.

“It happened so quickly, it busted all the glass out and it was an absolute disaster.

Mr Petersen said his McGrath office had been flooded three times in less than 12 months.

“It’s starting to wear a little bit thin.”

Molong, 35 kilometres north-west of Orange, has attracted tree changers in recent years and new businesses moved into its heritage main street buildings.

Wendy Henry, who owns the Booful homewares shop, lost much of her stock.

“The force of it has been unbelievable. It smashed everything inside to pieces.”

She said wooden pallets were swept from the highway down the main street, busting through the windows of about five shops.

Waters were receding in Molong’s main street later on Monday, while State Emergency Service and Fire and Rescue crews began a massive clean up.

It came after both agencies launched into action about midnight, doorknocking homes, beginning evacuations and helping the ADF rescue people stranded on roofs.

Tweet from @christophert77

Stay off roads: Premier

Premier Dominic Perrottet urged people in flood-hit areas to follow emergency warnings, saying they were not released “for the sake of it”.

“It may be the case that you don’t see flooding around you when those orders are put in place – that is because we expect and predict further flooding moving forward,” he said.

He urged people not to drive through floodwaters, saying a significant number of recent rescues were because people tried driving on flooded roads.

“You wouldn’t drive through a bushfire – don’t drive in floodwaters.”

The NSW SES responded to 33 flood rescues and 462 requests for help in the 24 hours to Monday morning.

NSW Emergency Services Minister Steph Cooke said exhausted SES volunteers would be bolstered by help from New Zealand as soon as Tuesday. The call had also gone out for support from the US and Singapore, as NSW’s flood crisis showed no signs of easing.

Tweet from @AymonBertah

Three new evacuation orders were issued later on Monday, including for people in low-lying areas of Eugowra, where flash-flooding is occurring.

There was also major flooding at Bathurst, west of the Blue Mountains, after heavy falls over the Macquarie River catchment on Sunday. There was a possibility that levees around the regional city could overtop on Monday afternoon.

Freight train derails in Victoria

There were also wild scenes in Victoria, with shipping containers strewn across tracks from a derailed freight train, closing the rail corridor to Adelaide.

The 1.7 kilometre-long train with 55 carriages derailed near Inverleigh along the Hamilton Highway outside Geelong about 5.30am on Monday.

Sixteen of the carriages derailed, sending dozens of shipping containers tumbling.

No one was injured.

“We know there was heavy rainfall and some flash flooding in that area but at this stage it’s too early to know what the cause was of the train derailment,” Victoria State Emergency Service chief officer Tim Wiebusch said on Monday.

“We are lucky we weren’t dealing with a passenger train in this instance and that the crew on board that freight train were also unscathed.”

The Australian Rail Track Corporation said no dangerous goods containers were impacted.

The corporation said the Melbourne-Adelaide rail corridor had been closed and affected customers notified.

The Office of the National Rail Safety Regulator has been notified and the Australian Transport Safety Bureau has taken control of the site.

The bureau’s chief investigator for transport safety will conduct the inquiry.

Mr Wiebusch said it could take more than a week for the wreck to be removed, as authorities worked out how to get heavy machinery to the site.

Victorian Transport Association chief executive Peter Anderson said flooding had caused significant road and rail freight challenges in the state and called on the state and federal governments to do more to repair the network.

He said with the rail link between Melbourne and Adelaide closed, road freight was expected to increase.

“Freight will always find a way to get to customers and consumers, particularly during our peak season leading into Christmas,” Mr Anderson said.

“With the expected increase in heavy vehicle traffic we ask all motorists to take additional care on the roads to prevent accidents and keep everyone as safe as possible.”

Meanwhile, the focus of the wild weather shifted to Tasmania later on Monday. The weather bureau said heavy rain was expected across the island state’s south-east and lower east on Tuesday, ahead of a cold snap.

Rain falls of up to 60 millimetres are expected on Tuesday, with higher totals possible in some areas.

“Recent rainfall means rivers are continuing to rise, with flooding occurring in northern catchments, and the possibility of additional river rises following forecast rainfall,” BOM said in a statement.

“Areas of flooding may also develop in the south and east from Tuesday.”

-with AAP