TM 10-3930-669-34 13-2.  MAST ASSEMBLY REPLACEMENTIREPAIR (CONT). WARNING • Inner rail assembly weighs 330 lbs (150 kg).  Attach suitable lifting device prior to removal to prevent possible injury to personnel. • All personnel must stand clear during  lifting  operations.    A  swinging  or  shifting  load  may cause injury or death to personnel. NOTE Position secondary chains clear of inner rail prior to removal of inner rail. (11) lifting device, roll inner rail (48) toward bottom of mast assembly (15) and remove two rollers (49) and shims (50) from inner rail. 13-10