FIG. 1 is a perspective view of a traction unit, showing our new design, the broken line showing is for illustrative purposes only and forms no part of the claimed design;

FIG. 2 is a perspective view thereof;

FIG. 3 is a right side elevational view thereof, the left side elevational view being a mirror image;

FIG. 4 is a front elevational view thereof;

FIG. 5 is a back elevational view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.