"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 the services under express or implied contract. Contractual services shall include: travel; freight; express; parcel post; postage; telephone; telegraph; utilities; rents; printing out; 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. (1985 Code § 7-103)