The fleet of 55 10-car trains, which will service customers across the Central Coast, Newcastle, South Coast and Blue Mountains have been undergoing testing after a later-than-expected arrival in December.

The first of the trains to roll off the assembly line were expected to arrive by ship in March last year.

The Central Coast and Newcastle line is set to receive the trains first, months ahead of the Blue Mountains line and more than a year ahead of the South Coast.

Significant track, signalling and station modifications have been made to cater for the trains, including platform extensions at Adamstown and upgrades at Hamilton.

The new trains will replace the ageing V-sets, which are due to be retired by 2022 after four decades of service.

"When the trains first arrived, on-track testing involved using a locomotive to haul the carriages. What we're seeing today is a really exciting milestone because they're now travelling around the network under their own power," Mr Constance said.

"Over the next few months you'll see more of these trains on the network as we progressively test all train systems including Automatic Train Protection, passenger door systems, passenger information, CCTV, ride comfort as well as the maximum speed of 160kph. We'll also be using this time to familiarise the train crew with the new operating systems and technology on board."

Minister for Regional Transport Paul Toole said work was continuing on important enabling works across the intercity network.

"These are modern trains featuring the latest technology, so we need to ensure we upgrade the infrastructure on the network to accommodate them," he said.

"Work is also continuing on sections of the Blue Mountains Line, which will enable customers living between Springwood and Lithgow to experience a new train for the first time since the last of the V-Sets were introduced in 1989.

"This work, along with the construction of the new maintenance facility at Kangy Angy, has helped to create around 1600 local jobs."

The Rail, Tram and Bus Union have previously labelled the new fleet as a "lemon" despite an independent review declaring the $2 billion fleet "safe", and raised concerns for the security of operator jobs.

In December, the Newcastle Herald reported, the RTBU's criticism of the South Korean-made trains came in response to release of an "expert safety review".

The NSW government commissioned the review after union concerns about how the trains will operate.

Drivers will become responsible for operating train doors on arrival and departure from stations, and for carrying out a safety check process.

Cameras will be used to monitor the train and platform, rather than a guard watching from an open door at the rear of a train.

The trains can operate without a guard, which the union has previously criticised, but the NSW government maintains their positions will not be disposed of, rather changed to a customer-service oriented role.