A Line
- A (Los Angeles Railway)
- A (New York City Subway service)
- A Line (Los Angeles Metro)
- A Line (RTD)
- A Line (Valley Metro Rail)
- A-Line (Hamilton)
- A-line (clothing)
- Aline (disambiguation)
- Arterial line
- Atlantic Coast Line Railroad
- A–A line
- Line (disambiguation)
- Line A (Buenos Aires Underground)
- Line A (disambiguation)
- Metro A Line (Minnesota)
- RER A
- RapidRide A Line