Delays are expected across the Sydney rail network this evening after an early morning fatality at Wentworthville and an operational issue at Central.

In a series of updates on Twitter, Transport for NSW advised commuters to “allow plenty of extra time to travel”, avoid boarding overcrowded services and stay aware on busy platforms.

Buses will replace trains between Blacktown and Richmond on the T1 Western Line, and those travelling from Wynyard and Town Hall have been asked to walk to Central instead due to overcrowding on platforms.

"Ongoing delays" are also expected on the T1 North Shore and Northern, the T2 Inner West and Leppington, the T3 Bankstown, the T5 Cumberland, and the T8 Airport and South Line lines.

Live updates are available on the Transport for NSW website.