To elaborate further: The ruling grade from McEwen to S-Wye is 1.5%, with a short section of 2% between S-Wye and Sumpter. The uphill run does not work either #19 or #3 hard enough to require keeping an injector going. Likewise, on the trip down it is not possible to keep the brakes set for any length of time without coming to a stand still. Knowing when and how much to apply the brakes does take some experience, but the chances of loosing control are close to nil. The only real trick is that when leaving Sumpter you have to be on the brakes almost as soon as you start rolling. That should not pose a problem who has learned the controls and has an experienced engineer to guide them.