In Oktober 2004, a contract was signed in Algiers whereby Siemens AG acquired a 51 percent majority holding in ESTEL, a subsidiary of SNTF.

ESTEL was established in 1989 as a subsidiary of SNTF. Its main areas of activity are the planning, installation, commissioning and maintenance of signaling and safety systems.

With a workforce of 150, SNTF has already cooperated closely with Siemens in the installation of relay interlockings in various parts of Algeria.