The ornamental design for a goosenecktrailer, as shown and described.
FIG. 1 is a front perspective view of the gooseneck trailer showing the new design;
FIG. 2 is a right side view of FIG. 1;
FIG. 3 is a left side view of FIG. 1;
FIG. 4 is a front view of FIG. 1;
FIG. 5 is a rear view of FIG. 1;
FIG. 6 is a top view of FIG. 1; and,
FIG. 7 is a bottom view of FIG. 1.
Applicant makes no claim to the structure shown in broken lines in the drawings. Furthermore, Applicant notes that the markings on the drawings are for shading purposes only, and are not to be considered a part of the design of the present invention. The Applicant also notes that the claimed subject matter depicted in the drawings is not limited by any description given of the embodiment.