Which companies provide the signal system for each line of Shanghai Metro?

Before 2005 and 2006, the subway signal systems in Shanghai mainly included Siemens, GRS, Alstom and Bombardier.

Now, after a series of integration and transformation, Casco (formerly Alstom technology) and Terez (formerly Alcatel) have basically taken shape as signal system integrators. Of course, some old equipment is still in use, such as GRS of 1 line.