Even before 2017, CR had an ambulance on wheels that would go to remote areas and stay for a few days so that patients in surrounding areas could avail medical care. So railways (if wish) could convert its AC sleeper rakes into ICUs with little modifications.
Only problem would be taking stretchers inside coaches to their beds (berths). But those who can use wheelchairs can easily be accommodated. All pit lines have water. Pantries as makeshift clinics could have water purifiers installed. The pit lines also have limited access, so more convenient than platforms. AC ducts could carry oxygen (with little modification) to each bay ventilators. HOG loco at the far end could supply electricity.