Where is a senic line on day trip from Sydney ?

["Yas. Kan." <yska@yahoo.com>]

Dear All,
 
I am a fan of Australian railway in Japan.
I have a plan to travel Sydney and I should very much like to
take train while I am in Sydney.
Could you tell me where a scenic line is on one day trip ?
 
Regards,
 
Yas. Kan.