Twelve American cities are operated with a subway. These railway transit systems, elevated and underground, represent a vast labyrinth that enables thousands of people to move around every day without using the often congested streets that we all know too well. If the subway is the favorite transportation solution for the major part of the population, it can prove to be a real puzzle for disabled people. How can you feel safe in a congested and confined environment? How can you find your way around when you have to deal with complex stations? How can you reach the platforms in an environment where elevators are rare or even nonexistent?