Do you have the prints for the job? Are they geared or gearless? Does this happen only on normal? Are you dropping the gate switch, door locks or safety circuit? "UA" for up and "DA" for down are self holding in respect to other relays-you may have a problem with the relay contacts that feed the self holding UA or DA. If it happens in both directions check your "CS" relays-the contacts on all the IBM style relays are prone to issues.