The Ford Atlas Concept at its Detroit debut.

Redesigning an icon is never easy, especially when it’s a proven winner that has dominated the traditionally conservative full-size truck market for decades on end.  But that’s precisely what Ford Motor Co. decided to do with the complete makeover it has in store a little more than a year from now with the next-generation F-Series.

The Detroit maker is being cagey about the exact timing of that launch, never mind specifics of the replacement truck – but it has also made it clear that a key goal will be slashing mass and boosting mileage without sacrificing the capabilities and durability of the rugged workhorse.

We got a sense of what may be in store during the Detroit Auto Show, this past January, when Ford literally dropped in on a media event with the gleaming silver Atlas Concept. And the images here of two other, earlier concepts – dubbed the Bullet Train and the Locomotive — reveal what went into the show car’s development.

An early sketch of the Ford Atlas Concept.

“The Ford Atlas Concept previews the innovations that will transform what people expect from their pickup,” Raj Nair, Ford group vice president, Global Product Development, said at the unveiling. “With 36 years as America’s best-selling pickup, we are absolutely committed to setting the agenda in the truck market.”

There are plenty of examples of what can go wrong with a redesign. Toyota’s Scion division crashed and burned with the replacement of the boxy xB.  Ford itself failed to maintain momentum when it updated the original Taurus sedan.

A similar disaster with the next F-Series could be catastrophic, especially considering what is likely to occur on the engineering side.  Most industry sources anticipate Ford will migrate to an all or aluminum-intensive platform and body for the 2015 F-Series, a move that could shave off as much as 750 pounds of mass.  And the general rule of thumb is that every 100 pounds you cut yields as much as an extra mile per gallon.

The radical Bullet Train design.

“Part of our strategy is to put all our vehicles on a diet,” Ford Chief Operating Officer Mark Fields hinted to TheDetroitBureau.com.  But he also stressed that fuel economy alone isn’t enough.  “If anything, our goal is to improve capabilities,” and ensure that any new truck won’t burden users with increased operational costs.

The Atlas Concept itself features some intriguing design cues, such as the all-glass panel that runs the length of the roof, its distinctive headlamps, power running boards and active grille and active wheel shutters meant to reduce fuel-sapping wind drag around the truck’s engine and big tires.

But what appeared at Detroit’s Cobo Hall was relatively conservative, at least compared to the earlier prototypes that were melded into the Atlas.

What was Ford thinking about with those other two options?

The more macho Locomotive design.

The Bullet Train was the more radical idea, as its name suggested, putting a high premium on aero improvements that made it resemble the high-speed trains of Japan and Europe. That means a windshield that actually continued where traditional glass leaves off, sweeping far into what would be the normal roofline.

The idea may have seemed simply too radical but it could also have created other issues, such as meeting the latest federal roof crush standards, as well as finding ways to position a roof cargo carrier.

The Locomotive, on the other hand, moved to the conservative extreme, dialing in a design that looks more like a Hummer than an F-Series.  This take did offer some functional advantages, notably a hollowed-out storage compartment within the tailgate walls.  Truck buyers are always short of storage, something that has worked for Chrysler with the bin built into the side of the cargo walls.

While the Ford Atlas was one of the bigger draws at the 2013 Detroit Auto Show, insiders suggest the concept will go through some more significant changes before we finally get to see a production version of the 2015 Ford F-Series.