Thank you HSTEd.
Just a quick look tells me that Kendal to Shap Summit, 15 miles, c585' rise, av. gradient 0.75%. Beattock to Beattock Summit, 9 miles, c650' rise, av. gradient.1.4%.
An HST would laugh at these hills.
I foresee some heroic earthworks and soaring viaducts to keep the line...