track scan
There is a program called "Track Scanner" that you can use to measure the distance between any two connected track points in surveyor. Once you have this number, measure the difference in height between the two points. By dividing the distance into the difference in height, using the same units of measure, you will determine a smooth average percentage grade between the two points. You can then use the "get gradient" tool to see if you are on or close to the average grade.
This is not strictly prototypical, as a railroad would not necessarily restructure the entire Earth to build their ROW unless there is a compelling reason to do so, but it does give a good guideline. You will be close if the ruling grade is not excessive.
Track Scanner can easily be found on the DLS.
Hope this helps.
Bernie