"Contractual services", for the purpose of this chapter, shall mean services performed for the City by persons not in the employment of the City, and may include the use of equipment or the furnishing of commodities in connection with said services under express or implied contract. Contract services shall include travel; freight; express; parcel post; postage; telephone; telegraph; utilities; rents; printing and binding; repairs, alterations and maintenance of buildings, equipment, streets and bridges, and other physical facilities of the City; and other services performed for the City by persons not in the employment of the City. (2000 Code § 7-103)