"This chart depicts the track grades in the Derail Valley map. Triangles by each number point uphill. Numbers are color-coded based on steepness:
0 to 0.6 = white
0.7 to 1.3 = yellow
1.4 to 1.8 = orange
1.9 to 3.5 = red
Beyond 3.5 = purple (only one section of track)

A couple of notes:
This chart is not fully comprehensive for all track grades on the whole line. If it was, there would be so many numbers in some places it would be too hard to read.
More often than not, the grades posted on signs beside the track do not indicate the same percent grade in both directions. For example, a section of track indicated as “1.1” going one way might be flagged as “0.9” going the other. I think this reflects the fact that track grades are constantly changing to conform to the land. Wherever two grade signs on the same section of track differ, the chart numbers indicate the higher value.
Sections of track indicated as zero are not necessarily perfectly flat, but should be no more than 0.4% or so."