Sydney has an extensive suburban rail network operated by CityRail. Cityrail operates with at least a 30 minute frequency to all metropolitan stations (apart from the (dark blue) Carlingford Line and stations between Riverstone and Richmond on the (yellow) Western Line). There are usually 15 minute frequencies to major destinations and transit hubs such as Chatswood, Bondi Junction, Hurstville, Parramatta, Bankstown, Blacktown, and Liverpool. The Cityrail timetable has a weekday service and a weekend and holiday service.

During peak times 7am-9am and 5pm-6pm trains are faster, more frequent and more crowded. Expect severe congestion around Town Hall. The complex rail network sometimes experiences delays, especially during rain or excessively hot days.

The majority of Cityrail's suburban trains are not equipped with destination displays on the train and announcements can be inaudible. The displays on the platform are usually clear, but you need to make sure you know where you're going and keep track of the station stops.

All stations are equipped with CCTV and trains at night have designated NightSafe carriages and station areas with emergency intercoms and security patrols, making catching trains at night a viable (and cheaper) alternative to taxis.

Outside of operating hours, between 12AM (1AM on Fridays and Saturdays) and 5AM, NightRide buses are available on most routes within Sydney. Any CityRail train ticket is valid for the equivalent NightRide bus except a single. If you don't have a ticket, you'll need to buy a NightRide single from the driver, which is more expensive than a single for the train. NightRide buses stop at most CityRail stations and a few additional stops, but they don't travel on the same routes. If you intend catching a NightRide bus home, check the NightRide route map on the back cover of each timetable or at the station while you are waiting for your train.

On weekends check for trackwork before leaving for the station; CityRail will transfer passengers to buses if lines are closed for trackwork, and the process will add about half an hour to a typical journey. Trackwork will be advertised at the station for about a week before it begins. You need a the same ticket for the trackwork buses as you would for the train.

You must always purchase a ticket for the entire journey before boarding a train from either the ticket office or from the ticket machines that are located on most stations. There is no opportunity to buy a ticket onboard or at the destination. Ticket offices have limited opening hours at suburban stations, and outside of these hours you will need to use a machine. The ticket machines accept up to $50 notes but will give only $19.90 in change (in coins). They will also accept only 10 coins. Ticket offices accept Visa or Mastercard for a total ticket value over $20. A handful of ticket machines also accept Visa or Mastercard at major stations if you have a PIN.

Ticket inspectors will not hesitate to fine you and generally don't accept any excuses--unless if you say the ticket machine was broken at the station which you boarded the train, and then they will check that! If you accidentally buy the wrong ticket or forget to buy a ticket, honesty is not necessarily the best policy.

Within the city area there is a light rail system run by Metro Light Rail. It connects Central station to Sydney/Darling Harbour, Star City Casino and the inner western suburbs.