G'day anthonyg,
The answer to your question lies in the manual (as I always say; "when all else fails RTFM")! Anyway, to save you the trouble, there is a button in Surveyor under the 'Track Laying Tab' accessed through the 'Advance' Drop Down Menu known as the "Smooth Spline Height" button (it's the one in the top right hand corner of the Drop Down Menu). If you LMB click on this 'icon' and then click on any section of track, the surrounding terrain will magically raise or lower to follow the gradient of the track section you have selected. If the track is higher than the terrain, the land will form an embankment, if the existing terrain is above the track, a cutting will be created.
But the land will be 0.3 m to low and the teack looks like it's floting in the air you can fix this by setting the Spline Height 0.3m higher and bring the land to that hght then lower the Spline Height 0.3 it's a lot more work but it looks much better.
may be a better fix somewhere.
joe13