I still think it's drastic action and not something I would go for personally. One thing I would look at is how freewheeling the rolling stock is. I notice that a lot of modern rolling stock is not as freewheeling as say, an old Lima Mark I. Check back to backs etc. I ran a new 201 on A4Mallards layout with three sets of Dapol Megafret container wagons (each set = 2 wagons, so essentially 6 container wagons) and it ground to a halt in the corners where there was an incline. The wagons are poor runners, not free at all, and i reckon the 201s could do with more weight and 12 wheel drive because a Bachmann 66 pulled them and more no problems.
Either that or re-do the helix if it's causing too many problems. Big and annoying job that though!