Train passengers between Sydney and Newcastle will win some relief from crowding after 173 new seats were added to the route.
Two more 10-car Mariyung trains were added on Monday morning to the daily peak timetable on the Central Coast and Newcastle line.
They will replace eight-car sets and add more capacity to each service.
By next Monday, another two 10-car Mariyungs will replace eight-car sets on morning and afternoon peak runs.
The final two eight-car Mariyung sets on the Central Coast and Newcastle line will be replaced by 10-car sets later this year.
"More Mariyung seats in the peak on the Central Coast & Newcastle Line is an important step as we continue to deliver a high-quality intercity service," chief executive of Sydney Trains Matt Longland said.
"Around 45,000 trips are taken on the Central Coast & Newcastle Line every weekday, so this additional capacity ensures we are better prepared to get more people to and from work and home on the more spacious and modern Mariyungs."
Newcastle MP Tim Crakanthorp said the announcement was welcome news for the thousands of Novocastrians who rely on the line to reach work, university and Sydney appointments.
"Newcastle is a growing city, and our public transport network needs to keep pace," Mr Crakanthorp said.
"More 10-car Mariyung services mean more seats for local commuters and a more comfortable journey for the thousands of people travelling to and from Newcastle every day."
A total of 19 Mariyungs are now in operation on the Central Coast & Newcastle Line, servicing every station on the line.
NSW's first Mariyung train entered passenger service on the Central Coast and Newcastle Line in December 2024.
The trains have since been progressively rolled out on the Blue Mountains Line and South Coast Line.
The Mariyung fleet provides modern heating and air conditioning, two-by-two seating with extra legroom, arm rests and tray tables, charging ports for mobile devices and dedicated spaces for luggage, prams and bicycles.
The trains also provide the highest level of accessibility across the Sydney Trains fleet, with dedicated wheelchair spaces, accessible toilets, priority seating, CCTV and enhanced customer information systems.