## 9 Conclusions and Limitations  
This study emerged from renewed interest in terms as a sustainable means of transport, particularly in respect to the trend of remodeling historical vehicles for functions beyond passenger transport, such as catering, education, and work. However, these projects lacked theoretical and methodological references, such as design guidelines, technical instructions, handbooks, and analytical case studies, resulting in interventions being solely reliant on designers' creativity or specific contextual conditions. To address this methodological gap, we proposed a set of guidelines for redesigning terms for alternative purposes. These guidelines comprise a series of design steps, each detailed by roles, procedures, technical tools, and expected outputs and exemplified step-by-step through a concrete project. The guidelines were designed during a project for the new town of Gwangmyeong in South Korea, and based on the design team's research and direct experience with ATMosfera, a restaurant tram in Milan. The proposed guidelines represent a novel contribution insofar as they are the first to address this topic. This comprehensive study provided a design process with a solid practical framework, but versatile enough to be used in different contexts and adapted to the needs of stakeholders with varying structures and work habits. The guidelines are proposed as an exemplary case study for designers and interested parties intending to undertake tram redesign projects. However, given the significant research and study behind their development, they will likely be discussed as methodological tools in their own right and opened to scientific debate. This study contributes to such debate by outlining their effectiveness. Positive feedback can make this and similar work the basis for developing a shared methodology, strengthening its influence on project development as well as technical and economic evaluation. These results notwithstanding, this study has several limitations. First, the research-through-design approach upon which the study is based has been criticized for its limited generalizability, inherent subjectivity, and replication challenges. At present, despite the proposals for a validation methodology outlined in Section 2.4 and developed in Section 8, there is no universal consensus on the scientific validity of this type of approach [42] (p. 2); cf. [85; 86]. Second, the guidelines stop at the threshold of the executive stage as they do not go beyond the design development phase. As explained in Section 2.2, this decision was made to maintain methodological coherence, particularly insofar as the phases from construction documentation onwards require a different organization of work and the contribution of different specialists. As addressed later, this is an area where the guidelines can be further developed. Third, defining design phases in relation to their formal, universally accepted subdivisions, such as those followed by the AIA [82; 83], presents a challenge. It is difficult for a methodology that deals with an object such as a tram, which is halfway between an industrial product and architectural space, to organize the project in such a way that the steps satisfy the customs of both sectors. This study attempted to overcome this difficulty by subdividing the process into phases that seemed logically appropriate to the task, while indicating among the outputs of these phases the official documentation of an architectural project (i.e., _Pre-Project, Schematic Design_, and _Design Development_; see Sections 4-7). However, we recognize that alternative solutions can be explored, as this question is crucial in the drawing up of contracts among various other tasks. These limitations underscore the need for further research and development to enhance the applicability and robustness of these guidelines. First, future studies should validate these guidelines using tangible outputs.