Smartlock 400 System (SML400) is a computer-based interlocking (CBI) system designed specifically as a successor to Solid State Interlocking (SSI) for all signalling applications in the United Kingdom.

Compared with SSI, SML400 offers:

• Reduction in number of cross-boundry communications required due to increase in potential size of interlocking coverage;
• A reduction in the physical size of central interlocking equipment;
• Compatibility with current communications technology;
• Updated facilities for the maintainer: graphical interface, improved fault analysis;
• Improved application engineering tools for test and incident analysis.

Smartlock 400, retains the Trackside Functional Modules (TFM) and trackside communications link that are used with SSI.

It can interface with a conventional signaller’s entrance/exit (NX) panel and is also compatible with VDU-based Control Systems, such as the Integrated Electronic Control Centre (IECC), or Modular Control System (MCS).

Generic product acceptance for Smartlock 400 interlocking from Network Rail was received in April 2011.

Smartlock 400

Smartlock 400 – SSI Comparison