The ornamental design for a walkertruck, as shown and described.
FIG. 1 is a perspective view of the Walker truck of my new design.
FIG. 2 is an elevational view of one side thereof. The elevational view of the opposite side is a mirror image thereof.
FIG. 3 is an elevational view of the front end thereof.
FIG. 4 is an elevational view of the rear end thereof; and,
FIG. 5 is a top plan view thereof.
The broken line elements in FIG. 1, depicting a small child standing on the ground behind the Walker truck of my new design, are environmental elements and form no part of the claimed design.