The deadly Granville train disaster of 1977 still haunts survivors, says a woman who witnessed the bloody aftermath.

A ceremony has been held on Monday to commemorate the 39th anniversary of the day locomotive No.4620 derailed on its way to Sydney, leaving 83 dead and 210 injured.

A rose has been placed on train tracks to honour each victim following a ceremony at Granville Town Hall in the city's west.

June, who owned a nearby drycleaning business, says she helped victims wash blood off their faces as they streamed into her store on the day of the disaster.

'They were crying, we helped them,' she told ABC Radio.

'It still breaks me up.'

Survivors, emergency crews and those involved have kept in touch through a support group, which gathered on Friday ahead of the anniversary.

Rescuer Gerard Buchtmann said talking about the trauma was the key to mental recovery for emergency personnel and survivors.

'I could not describe to you the carnage and destruction that we saw on that day,' he told AAP.

'The first person to openly break (in the debrief) was me, and I was the captain.'

AAP