Taipei's public transport system, the Taipei Metro (commonly referred to as the MRT), incorporates a metro and light rail system based on advanced VAL and Bombardier technology. There are currently six metro lines that are organized and labeled in three ways: by color, line number and depot station name. In addition to the rapid transit system itself, the Taipei Metro also includes several public facilities such as the Maokong Gondola, underground shopping malls, parks, and public squares. Modifications to existing railway lines to integrate them into the metro system are underway.