TM 10-3930-669-34 NOTE • Position two secondary chains through center rail prior to center rail installation. • A pry bar may be required to position center rail in outer rail. (5) Install two shims (73) and rollers (71) on outer rail (61). (6) Install two shims (72) and rollers (70) on center rail (58). WARNING • Center  rail  weighs  361  lbs  (164  kg).    Attach  suitable  lifting  device  prior  to  installation  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. (7) Install center rail (58) in outer rail (61). 13-17