RULE 66.   (a) Helper Districts. (1) Trains of over forty cars exclusive of caboose will not be doubleheaded, except as hereinafter provided.  

     Helpers may be used between the following:

     Council Bluffs and Gilmore 
     Council Bluffs and Valley, via Sarpy 
     Valparaiso    and Wahoo 
     Valparaiso    and Brainard 
     Oconee        and Madison 
     Cheyenne      and Sherman 
     Cheyenne      and Dale via Speer 
     Egbert        and LaGrange 
     Salina        and Ellsworth 
     Lisbon        and Winona 
     Kit Carson    and First View 
     Carr          and Cheyenne 
     Carr          and Sherman 
     Carr          and Dale 
     Denver        and Boulder 
     Ogden         and Wahsatch 
     St. Joseph    and Hiawatha 
     Carden        and Hanover

       (2) Helpers may be run on any district when necessary because of storms, engine failures, to avoid running engines light, in moving engines to and from shops, or in moving engines from one district to another, provided the rating of the heaviest engine is not exceeded.

       (3) Double-headers may be run on any district provided the rating of the largest engine handling the train is not exceeded.

       (4) In case of an accident to any engine consolidation may be effected with another train and this consolidated train brought to a terminal as double-header if practicable.

       (5) When by reason of the acquirement of additional lines, change in grade, etc., it becomes necessary, helper service may be established where conditions are similar to those covered by the helper limits as above provided.

       (6) It is recognized that the exigencies of the business may require additional helper service to that provided for, in which event the matter shall be settled by negotiations between the management and committees, and provisions for pusher or helper service may be made by management and committees for pusher or helper engines on any district to maintain the tonnage intact over grades.

       (7) In the operation of multiple unit Diesel electric locomotives, the tonnage rating shall be the aggregate rating of all the connected units constituting one locomotive, except that where one or more of the units are inoperative out of the termina1 at which the crew takes charge of the train, the operative unit or units shall not be included in the calculation of the tonnage rating of thelocomotive, but shall be included in the tonnage of the train, and the tonnage rating of the remaining operative units out of the terminal will constitute the locomotive for tonnage rating purposes for the entire district over which the crew handles the train.

       When one or more units of a diesel are set out enroute, the remaining units shall then constitute the tonnage rating of the engine handling the train.

       When a unit of a Diesel locomotive becomes inoperative enroute, the tonnage rating shall continue to be the tonnage rating of all the units.

       (b) Outside of Helper Districts.  When trains of over forty cars, exclusive of caboose, are doubleheaded outside of helper districts, and the tonnage rating of the heaviest engine is exceeded, double mileage for actual mileage doubleheaded will be allowed.