[jclark003]

If you pulled hard from one end it's possible the cable is bound in the corner radius of the arch. If I remember correctly it the channel narrows the closer you get to the corner. If the cable is lodged in there you may need to reach in there with a cutoff broom handle or something to pry it out of the corner. Once done have your son gently pull from the top while you feed the cable from the bottom. If you can get several feet of slack moved up the arch with cable lube you should be home free. Cut the cable and pull the rest through.