MORE commuters would have to change trains to get to the city centre under a planned overhaul of Sydney's train system that will attempt to make trains run more frequently and reliably.

The overhaul would mean commuters from a clutch of stations in Sydney's west and north-west would lose direct services to the city, but they would be promised better and more regular services on the express line when they change trains.

"Transport for NSW is undertaking the most fundamental re-write of the rail timetable in a decade to ensure we get the most out of the current network for customers" ... Gladys Berejiklian. Credit:Janie Barrett

The principles behind the planned redesign, which remain controversial inside the transport bureaucracy, are expected to be laid out in the coming weeks.

They promise an easier to understand timetable and simpler and faster train movements.