Union says it raised safety concerns day before major train derailment

Multiple emergency services were called in to help manage traffic and remove the derailed freight train. (Supplied: Brendan Winkler)

The rail union says it raised safety concerns with a freight train operator about 24 hours before a major derailment of one of its trains in the NSW Southern Highlands.

Southern Shorthaul Railroad (SSR) is not allowed to operate for six weeks after five wagons carrying cement product left the tracks at a level crossing at New Berrima on Saturday.

Cement-maker Boral says it is looking at other ways to transport its product.

The New South Wales Rail, Tram and Bus Union (RTBU) says it raised safety concerns with the operator of a freight train the day before a major derailment.

Five wagons rolled and left the tracks at a level crossing at New Berrima in the NSW Southern Highlands on Saturday.

Holdco Holdings, which trades as Southern Shorthaul Railroad (SSR), is the freight train operator contracted to Boral's Berrima cement works, near Moss Vale.

The company's accreditation was suspended on Sunday by the Office of the National Rail Safety Regulator (ONRSR) as a result of the derailment, meaning it cannot operate for six weeks.

A crane was called in to remove the derailed freight train from the Berrima Road level crossing. (Supplied: Riley Sercombe)

RTUB locomotive division secretary Farren Campbell welcomed the regulator's decision to suspend SSR's licence.

He said a meeting between the union and SSR was held at 11am on Friday, about 24 hours before the derailment, to discuss reports from workers of inadequate procedures and training, aging rolling stock and a toxic workplace culture.

"We've resisted the urge to say, 'I told you so' with cupped hands, because that's not what it's about," Mr Campbell said.

"It's about making sure we can maintain safety standards of the NSW rail networks. It's about [ensuring] the company at the centre of this isn't able to shift the blame onto workers."

In a statement, the ONRSR said its decision was "not taken lightly", and it was looking at several incidents involving the company and was concerned further safety risks could emerge if action was not taken.

The RTBU said SSR was responsible for 20 per cent of freight movements on the Sydney Trains Network.

It said it was aware of two runaway events involving the company this year, including one in which a worker was forced to board a moving locomotive to bring it to a stop.

Farren Campbell says members had already raised safety and workplace concerns. (Supplied: RTBU)

Mr Campbell described the union's meeting with SSR as "cord