From Portland Afoot

Capital expenditures generally means one-time purchases by government agencies on things like land, infrastructure, buildings, and new vehicles. A government budget is generally divided between capital expenditures and operating expenditures.

In the case of TriMet, most capital expenditures in a given year are related to rail and rail station construction, though bus stop improvements and bus purchases are also substantial expenses. TriMet has relied heavily on Federal Transit Administration grants (largely the New Starts program) to cover the capital expenses of building the MAX system. These grants cannot be spent on transit operations without a change in federal law.