(a) These rules as originally adopted took effect on January 1, 1952. They govern all proceedings and actions brought after that effective date, and also all further proceedings in actions then pending, except to the extent that in the opinion of the court their application in a particular action pending when the rules take effect would not be feasible, or would work injustice, in which event the procedure existing at the time the action was brought applies.(b) Unless otherwise specified by the court, all amendments will take effect on either January 1 or July 1 in the year of or the year following their adoption. They govern all proceedings in actions brought after they take effect, and also all further proceedings in actions then pending, except as to the extent that in the opinion of the court their application in a particular action pending when the amendments take effect would not be feasible, or would work injustice, in which event the former procedure applies.