The ornamental design for a dualtrack, as shown and described.
FIG. 1 is a top perspective view of a dual track showing our new design;
FIG. 2 is a front view thereof;
FIG. 3 is a left side view thereof;
FIG. 4 is a right side view thereof; and,
FIG. 5 is a top view thereof.
The broken lines shown in the drawings are included for the purpose of illustrating portions of the dual track that form no part of the claimed design.