I was on the ride when it broke! With hindsight, I think it may be a restraint error. on the arm closest to buffalo on the row facing accel and dutchman, the two restraint open lights were on when the restraints were open. when they shut, the two restraint closed lights lit, but one restraint open light remained on (I don't think it was exactly labelled restraint open, but it was too that effect) the ride swung up, but presumably did a final safety check before inverting, caught the error and stopped. this was either a faulty sensor or restraint fault. I don't think it was a hydraulic leak as the hydraulic rams that raise the ride worked, and the restraint ratchet lock