Ключевые слова: accessibility, automatic, business, card, check, coin, commuter, control, crowd, door, electronic, enter, entrance, entry, exit, gate, gateway, insert, inside, leave, line, locked, machine, mechanic, metro, metropolitan, modern, pass, passenger, permit, person, public, rapid, row, scanner, security, singapore, singaporean, station, subway, system, technology, ticket, touch, train, transit, transportation, underground, way, work,