The All Terrain-Scout Transport was a lighter walker designed by the Empire to serve as a scout for larger AT-ATs and as a stand alone unit in heavily forested areas or other areas impassable by larger vehicles.
About this creation
This is my (mildly) modified version of the original Lego Imperial AT-ST.
The biggest problem I had with the original Lego version was that it only seated one passenger, since we all know it should seat at least two people (a common Lego trait). So I remodeled the interior and side panels to allow for two troopers to fit. This view shows the seating arrangement.
This is a view with the troopers in place. Its a bit cramped, but the Empire is about intimidation and fear, not comfort!
A shot of the troopers peering through the forward viewports. They appear happy to be spreading the Empire's influence....
This a view of the rear of the walker with a few greebles added for effect.