I didn't know this was required. For all the others, I didn't even think of that. Now that seems obvious. Thank you

Hello, I thought I should give a try to the belt madness challenges but I got a strange behavior with some underground belt. As a new player I am not sure what should happen exactly. The iron gear and the copper ore are stuck but I don't know why... https://nsa39.casimages.com/img/2018/06/14/1806141...