Section 13. An operating agency shall be liable in contract or in tort in the same manner as a private corporation. The members, employees, officers and agents of an operating agency shall not be liable as such on its contracts or for torts not committed or directly authorized by them nor shall said members be liable for any negligent or wrongful act or omission for which the operating agency would be liable under applicable rules of law, in which event any action either civil or criminal against the operating agency shall be the exclusive remedy for any injured party. The property or funds of an operating agency shall not be subject to attachment or to levy and sale on execution, but if such agency refuses to pay a judgment entered against it in any court of competent jurisdiction, the superior court, sitting within and for the county in which the agency is situated, may, by writ of mandamus, direct the treasurer of such agency to pay such judgment. The real estate of such an agency shall not be subject to liens under chapter two hundred and fifty-four, but the provisions of sections twenty-eight and twenty-nine of chapter one hundred and forty-nine shall be applicable to any construction work by such agencies.

An operating agency shall reimburse the Massachusetts Bay Transportation Authority and every railroad corporation for all reasonable costs and expenses incurred by the said transportation authority or such railroad corporation to relocate such of their respective facilities as are required to be removed as part of a project being undertaken pursuant to this chapter by such operating agency and as are necessary for the continuance of the common carrier services performed by said transportation authority or such railroad corporation. ''Facilities'', as used in this paragraph, shall mean poles, tracks, switches, wires, conduits, cables, signals and structures and in addition thereto equipment appurtenant to any of the foregoing.