More than 300 train services a week will be added to the two main rail lines between western parts of Sydney and the CBD from November when a new timetable is rolled out to cope with record growth in commuter demand.

With the T1 Western Line under the greatest strain from overcrowding, the state government unveiled plans for about 250 express trains each week between Parramatta and the CBD on that link, which includes 20 during peak hours.

Sydney Trains will also start a new direct link between the inner west and Parramatta on the T2 Line on weekdays. Inner-west services to Sydney's CBD will run as frequently as every six minutes during peak periods.

The other major changes to the Western and Inner West lines – some of the busiest on the city's overstretched network – include a doubling of late-night services between the CBD and Penrith on the T1 Line. Some passengers, however, will have to switch services at Parramatta.