In 1957, 5631 was "available" at Clyde RH as power for a chartered excursion to Savanna and Galena, IL. 5631 was to pull the train from Chicago to Savanna and 5090 was scheduled to do the honors from Savanna to Galena. Dry weather conditions forced the decision to use a Geep, rather than the O1a, out of Savanna.
At Aurora, after loading passengers and,takin' water, the Engineer told the Fireman that he could handle the chores to Sav. and THAT he DID !!! He, the Fireman, told me he checked his watch when he pulled at Aurora and it was exactly 0830. As the engine drifted by the old Savanna Tower he took another "peek" at the watch and noted the time - 0941. The pay miles for that segment of RR is 108, which they covered in 71 minutes.
Keep
in mind, when calculating "average" speed, that there are certain locations that DEMANDED that the speed be reduced due to curves and other conditions. Steward Jct., Rochelle and the curves above Oregon come to mind.
In all likelihood, no other train had EVER made that same trip in that length of time and, it's assumed, no other train EVER WOULD again !!
Karl