Finally found it! It's Google Earth Pro. Tried it for the eastbound CZ at Granby CO for my upcoming trip. Juckins.net sez it's average lateness there is 2¼ hours so I set the date time data for the average delayed time of about 5:27 pm and got this sunlight adjusted view at Granby:Once upon a time Google Earth (I think it was) had a feature that would allow selection of date and time to see what it would look like at various times.
Can't seem to dredge it up now, but perhaps someone else knows how.
Later, when the train gets to Denver, it'll be dark there but even at this average lateness (2¼ hours) looks like you'd get to see lights of Denver as you descend after Granby as the Sun sinks slowly in the West.
At least that's what Google Earth Pro leads me to believe.