Making a model of a tram from card is straight forward. There are a number of models that can be downloaded from the internet without charge. A card tram can be a complete stand alone static model, or a card body for fitting to an existing chassis.
My trams are of the latter type, and are all freelance designs. Freelance because I am more interested in the technology of trams than replicating an exiting form. Freelance designs permit me to design bodies for existing chassis. Generally the chassis was not originally meant to be a tram and if the dimensions are the same as an existing tram it is luck rather than judgement at play.
Unless otherwise stated all the models I make available for download are freely available to do what you as an individual modeller to do with as you please.