Spray pan with vegetable pan spray. Make chocolate pound cake batter. Pour batter into bottom half of prepared pan (the pan half without the hole) up to the pan rim. Snap top half of pan in place. Tie halves together with household string to prevent rising cake batter from forcing pan halves apart. Bake 50 minutes. Remove top of pan and continue baking until toothpick inserted in center comes out clean, about 10 additional minutes. Cool in pan on cooling grid 10 minutes. Replace top of pan, turn cake over and remove bottom pan; let cake rest in top pan half until completely cool, at least 4 hours.
Trim off smoke stack from cake. Stand on foil-covered cake board. Ice windows smooth. Pipe tip 21 spiral on front of engine with white icing; attach sour cherry candy. Cover cowcatcher (bottom front) with tip 21 green icing lines. Cover engine with tip 16 blue stars. Add two tip 21 zigzag rows over engine in white icing; decorate with candy-coated chocolate dots. Spatula ice roof; attach licorice side-by-side to cover. Place cinnamon dots around windows. With icing, attach chocolate chip cookie wheels, fruit jelly wheel centers and candy sticks. Trim 1/2 in. off flat bottom of ice cream cone; press into cake. Pipe tip 1M white icing spiral into cone "smokestack". Add nonpareils and sour cherry candy.