I'm stumped. There are two thing's I can think of right now but a few that don't make sense. One happen's to be couplers. Why is there a hole straight through the knuckle and what are those four hole's on the side for? Another thing, if it's trains vs. trucks then why do trucks haul truck side frame's, wheel's, coupler's, rail and other thing's while the railroad use's trucks for MOW and even hauls them? There's a catch 22 here that I don't get.