Posted 28 April 2018 - 05:55 PM
I might have it wrong, but that's not my understanding. I thought the rail fare is based on the lowest bucket, while the Saver fare (which is not available for the rail fare portion of a sleeping car journey) is lower than the lowest bucket. If I'm correct, then the "cheapest coach price possible" is less than what your method would produce.
You are correct that the Saver fare is lower than the rail fare. The rail fare is always the lowest bucket Value fare. However, Saver fares are not available on some routes or dates, and carry some limitations (primarily regarding refund and change policy) that don't apply to the Value fare.
And as to why you anyone would want to know the lowest possible Value fare, if your dates are flexible or you're on a budget, it can be useful to know the best possible price, as you might want to wait to book or look for a different date, if a significantly lower fare is possible.
Routes Traveled: Silver Meteor, Silver Star, Crescent, Lake Shore Limited, California Zephyr, Sunset Limited, Texas Eagle, Ethan Allen Express, Empire Service, Maple Leaf, Adirondack, Acela Express, Northeast Regional, Keystone Service, Downeaster w/ Great Dome
Wish List: Auto Train, Cardinal, CONO, Empire Builder, Southwest Chief, Crescent (overnight), Adirondack w/ Great Dome