Another 690 jobs will be cut from RailCorp in the latest changes to Sydney's train system.

But the cuts will not affect the number of drivers, guards or station staff, Transport Minister, Gladys Berejiklian, said at a press conference on Friday morning.

Job cuts ... RailCorp are to cut 690 jobs. Credit:Kate Geraghty

Fairfax Media also obtained a high-level RailCorp document which sheds more light on the large-scale plan to abolish the position of station managers and other rail staff, raising questions about the future safety of services.

The internal RailCorp document which is labelled commercial in confidence targets station managers, saying their role will no longer exist as part of a major staff restructure.