How to access the social promotion spaces if you are a public or non-profit entity? 

With the aim of disseminating the actions of social service entities and the public sector that require it, Ferrocarrils de la Generalitat de Catalunya (FGC) grants spaces so that non-profit institutions with social purposes can display and inform FGC customers of their projects and activities.
To apply for one of the social advertising spaces, you must first fill out the form on the FGC website, under the sectiont https://www.fgc.cat/en/about-us/social-responsability/collaboration-entities/