It cost Millions of Dollars to restore the boiler and Royal Hudson to Top Condition again!
Fans come from all over the world to see this prestigious Train!
It was restored for our 2010 Olympic Winter Games.
If I remember correctly up hill or wet tracks were a problem for the steamers.
I believe to gain traction they had the ability of using forward track, sand sprayers.
So possibly because of addition weight, and wet tracks, the extra loco was also utilized.