Private funding and support for subway construction and operation has been generally limited to advertizing and franchising associated with station facilities and areas. The great cost and negative revenue status of virtually all public mass transportation systems does not fit any private investment or development model.
Transportation authorities have successfully found joint operation and maintenance contracts with private firms to the mutual benefit of public owners and private operators of transit systems. Public-private contracts of this type have succeeded in several European countries, but are uncommon in the U.S.
