(a) General rule.--The testator or settlor in the instrument establishing a trust may prescribe the powers, duties and liabilities of the fiduciary regarding the investment or noninvestment of principal and income and the acquisition, by purchase or otherwise, retention, and disposition, by sale or otherwise, of any property which, at any time or by reason of any circumstance, shall come into his control; and whenever any such provision shall conflict with this chapter, such provision shall control notwithstanding this chapter, unless the court having jurisdiction over the trust shall otherwise decree pursuant to subsection (b) of this section. In the absence, however, of an express restriction to the contrary in the trust instrument, the fiduciary may invest in any investment authorized by this chapter.

(b) Exception.--Where the instrument establishing a trust contains a restriction on the fiduciary's power of investment and the court having jurisdiction over the trust finds that adherence to the restriction is impractical or that the existing or reasonably foreseeable economic conditions are so far different from those prevailing at the creation of the trust that adherence to the restriction might deprive the respective beneficiaries of income and principal of the full benefits the testator or settlor intended them to enjoy, the court may release the fiduciary from the restriction to such extent and on such conditions, if any, as the court may deem appropriate.