## 2 Literature Review  
Metro stations can be categorized according to the framework proposed by [PERSON] [7], who views metro stations as significant urban projects or large-scale urban artifacts. These stations involve transforming iconic city areas through repurposed infrastructure and/or increased density. Methodologically, metro stations are more than just transit network nodes; they also function as integral urban spaces, or \"node-places\". This concept of node-place was initially applied in Santiago de Chile [8], where it arises from the continuity created by modal exchanges between various transport modes or the high density of activities in a given location. However, [PERSON] [9] argues that spaces within large infrastructures, such as metro stations, risk losing their sense of place and becoming \"junkspace\". This term refers to pedestrian circulation areas lacking accessibility, formed through the accumulation of layers that fail to correspond to the surrounding environment in terms of meaning or proportion. Metro stations, as node-places, present multiple challenges when it comes to ensuring proper accessibility. Modifications to the circulation space can lead to new pedestrian flows, route alterations, shifting preferences, emerging bottlenecks, crossflows, new areas of congestion, and changes in user interactions. Furthermore, in disciplines like architecture, geography, and health, challenges arise when adapting existing spaces, such as modifying the sidewalk next to the station to incorporate tactile paving or installing ramps and handrails. Various manuals have been created to implement accessibility standards, though many focus primarily on public spaces rather than considering the metro station as a node-place. This gap presents an opportunity for researchers to design or recover mobility spaces as integral places within the city, addressing the issue of accessibility improvements. Based on guidelines such as the REDEFINE (Manual de Recomendaciones de Disefio para Proyectos de Infraestructura Ferroviaria), developed by MIDEPLAN (Ministry of Planning) and SECTRA (Transport Secretariat) [10], metro stations as node-places can be divided into five pedestrian circulation zones, with the platform-train interface being the most complex area [11]. Currently, all circulation elements within a node-place must incorporate universal and accessible design inside metro stations. According to Chilean Law 20,422 [12,13], accessibility is defined as the condition that environments, processes, goods, products, and services must meet to be comprehensible, usable, and practicable by all individuals, ensuring safety, comfort, and autonomy. In Chile, existing manuals primarily focus on the areas surrounding metro stations. Key national documents include:  
* REDEFINE developed by MIDEPLAN and SECTRA [14], mainly applied to interurban train stations like Metro Valparaiso, Biotren, and Tren Chillan--Central Station, but not for Santiago's metro stations. * REDEVU, developed by MINVU [15], is commonly used for urban roads, particularly around metro stations. * Cicloinclusive Manual for Cycling [16], which provides design recommendations for cycle lanes and facilities. * Traffic Signage Manual [17], which, like the REDEVU manual, is used for urban roads, addressing traffic light programming, demarcations, and other details. At the international level, [PERSON] [18] recommends that the combined vertical and horizontal gap between the train and platform for disabled passengers should not exceed 30 cm, with an optimal design gap of 20 cm. The Rail Vehicle Accessibility Regulation [19] states that when the vertical gap exceeds 5 cm and the horizontal gap exceeds 7.5 cm, a boarding device is required for passengers with reduced mobility. European standards [20] dictate that public transport vehicles should allocate 1.50 m by 0.90 m for wheelchair users to maneuver. They also specify that a maximum gap of 5 cm by 5 cm is ideal, with anything above 10 cm by 10 cm being unsuitable.