I have replaced Driver's with Traction Tires with Drivers which do NOT have Traction Tires...and been very pleased with the results.
I have been lessening my Grades over time.
I believe most Model Railroaders fall into the category of simply doing 2% or higher grades.
Except I began to test my N Scale Locomotives across the board and found a significant difference when the Grades approached 1.75%.
Further, there was a Series of Articles on the Physics of N Scale in N Scaler Magazine in the early 1990's which came to a Mathematical Conclusion of a Best or Optimal Grade at 1.73%.
My Testing Concurs
Except into a turn, the lateral forces act upon the Grade increasing it's effect. Basically causing a 1.74% Grade to act as if it is a 2% Grade. By lessening the grade to 1.5%, the overall effect was minimal.
This was accomplished ...
AFTER reading BNSF and UP Prototype Specifications, I settled on a continuous grade of 1.5% for straights and radius. This also add stabilization and keeps the momentum of a train in motion by not simply changing the Grades from a Straight into a Curve. I do not believe lessening a grade further to say 1.4% would have a marginal positive effect upon my model railroad.
After lessening my grades...I found Traction Tires not only not necessarily but in fact a nuisance.
After 4-5 hours of use, they can slip their driver and play havoc with the crank rods. Causing them to either ping off or bend and making me do a complete tear down along with re-quartering the whole mechanism. Plus, I believe they add grit/grime to the rails, as well as not the best concept for DCC with sound with conductivity in mind.
Though I have O and HO Scale Layouts...I am only speaking of N Scale. I expect the results may be similar but I have not tested such a Theory.
Hope this helps...
Modeling for now the Central Pacific, as the railroad began to learn from it's own mistakes post 18882.
The Central Pacific began to lessen their grades of 2.2% after that date.
This is a helluva way to run a railroad, but I am not sure when Prototypes began to adopt Standard Grades at 1.5%.