The salvage operation to remove the truck began at 8pm on Monday night and took a number of hours. Northbound lanes of the motorway were closed to traffic for the operation.
A NSW Police spokesman said inquiries were continuing into how the truck became stuck.
The white Freightliner prime mover, which had South Australian licence plates, was travelling from Clyde in Sydney’s west to Mayfield, when it hit the guard rail and blocked the ramp.
RMS had issued a permit for the haul and a pilot vehicle was leading the prime mover when it became lodged. A police car was also travelling with the truck at the time.
The male truck driver was not injured.
Rural Fire Service crews were called in to assist with fire protection during the evening’s salvage operation.
A bridge guardrail on the exit ramp was damaged as a result of the incident and the exit ramp will have a reduced speed limit of 60 kilometres per hour until mid-year, when the guardrail can be permanently repaired.
Motorists are advised to drive to the conditions and follow the directions of signs and traffic control.
A spokesman for RMS said the road authority was investigating the incident but would not comment on the identity of the company responsible for the vehicle’s movements.
«The permit provided [to the company] includes a number of conditions for the operator to comply with including the height, width and weight of the load, and how it is positioned,» he said.
«The operator is ultimately responsible for carrying out the safe transportation operation.»
Wallsend MP Sonia Hornery urged RMS to «thoroughly investigate what went wrong here».
«Someone has messed up because it is obvious that the truck was never going to fit across that bridge,» she said.
«Someone needs to be held accountable and the details made public.»