Line 12 may refer to several railway routes:
Asia
edit- Line 12 (Beijing Subway), China (under construction)
- Line 12 (Dalian Metro), China
- Line 12 (Guangzhou Metro), China (under construction)
- Line 12 (Shanghai Metro), China
- Line 12 (Shenzhen Metro), China
- Line 12 (Mumbai Metro), India
- Downtown MRT line, numbered 12, Singapore
- Putrajaya line, or Line 12, Malaysia
- Toei Ōedo Line, originally Line 12, Tokyo, Japan
Europe
edit- Line 12 (Barcelona Metro), a shuttle train on the Barcelona–Vallès Line, Spain
- Line 12 (Madrid Metro), Spain
- Line 12 (Moscow Metro), Russia
- Paris Métro Line 12, France
- S12 (ZVV), Zurich, Switzerland
North America
edit- 12 (BMT rapid transit service), New York City, US (defunct)
- Mexico City Metro Line 12, Mexico
South America
edit- Line 12 (CPTM), São Paulo, Brazil