§ 78. Relief after judgment on obligation constituting trust claim. If a trust beneficiary shall recover judgment against the trustee upon the obligation constituting the trust claim: (except in the enforcement of a lien as provided in articles two and three of this chapter)

(a) execution upon the judgment shall not be levied upon any trust asset;

(b) to the extent of trust assets affected by proceedings to enforce the judgment, the proceedings shall be deemed to be for the benefit of all trust beneficiaries who would, at the time the proceeding is instituted, be entitled to maintain an action to enforce the trust, and the provisions of section seventy-seven of this chapter shall apply in any such proceedings.