I would use the 'Apply Gradient' tool. You can find this under Tracks>Advanced Options.
You have to type in the gradient percentage, though. Two percent is considered remarkably steep for Class I railroads. A 1.5% grade wouldn't be that bad. A 1%, is a common gradient. I depends though, what your looking for. Steep gradients can be used for inter-city routes, while nice and gentle to represent long distant Class I routes.
Now that I've covered grades a bit, type in "FMA" and search is via "Title" on the Download Station. You'll find an entire elevated trackage system that is an embankment spine system that you can do just about everything with. The only problem would be the texture, it is predetermined, so if your doing a certain region with dirt, that wouldn't do. However, if winter is your choice, they offer a winter series that will do perfectly. I would also look at their other offerings, they do make top-notch content that I've got all of. I can say, they do know how to make content.
If you don't find the system to your use, you can always use the "Smooth Spine" feature for trackage. Go to Track>Advanced Options and the icon is a flat line with a red and white pattern. What this will do is smoothen the height of the landscape to conform to your trackage height. Click on a section to try it out. If it seems too steep of an embankment, click on it until you either max out the amount of smoothness or you find your proper embankment. Note that it'll only go so close to the track. You'll have to lower your track 0.2 units of height for it to be on the embankment top properly. Otherwise, your track will hover 0.2 units high. That's not all that noticeable from the top, but it clearly visible when viewing up the embankment or next to it.
Cheers,
Joshua