The fire has been contained and crews are establishing control lines.
Firefighters had to drive in off road to get to the scene and carried out a direct attack on the grass fire.
The size was approximately three hectares, and a small section crossed the railway line into the ACT.
A rapid response by New South Wales Rural Fire Service, supported by ACT units meant the fire was under control very quickly.
At the height of the incident there were 13 appliances on scene, two commanders and two helicopters.
Aerial support included an observation helicopter and medium water bomber.
New South Wales Rural Fire Service had seven trucks respond. The ACT Rural Fire Service still has five tankers at the site.
The railway remains closed. Smoke may linger in the area.
Cause is unknown at this stage.