Transition into (and out of) a gradient....?

[JimmyB]

When you bend metal, it stretches more on on side than the other, and though you may be able to straighten it I doubt it will ever be the the same. For horzontal bends the odd "wiggle" won't matter, bur for vertical bends humps in the track are a different matter.

 

[dunnyrail]

both work well.
only difference is, that it is nearly impossible to undo upward- or downward bents in the rail. (thinking of future re-use)

Another option would be to support the rail between two blocks of wood and use the mk1 boot by gently stepping not jumping up and down on the said rail.

 

[stockers]

If, using my plywood method to bend the track, you do the reverse...ie bend the plywood so that it matched more or less the bend in the track, screw the track to it, then let the plywood spring back go to its flat state (maybe with a little extra encouragement) it will bring the track back to nice and flat again

Yes - or tread on it!