The existing door and general relay panels contained ageing relays, sockets, connections and terminal components that were approaching the end of their operational life. The number of relay malfunctions was increasing, while modifications made during the service life of the trains had resulted in relay contact loads that were no longer optimal. The existing configuration also offered limited spare capacity for future modifications.
A modern replacement therefore had to improve reliability and safety without requiring major changes to the trains. The replacement solution needed to fit within the available installation space, use the existing mechanical mounting points and remain compatible with the train wiring and connection locations. During the engineering phase, several panel concepts were evaluated to demonstrate compliance with these space constraints. Obsolete functionality had to be removed, while new functionality and spare positions had to be incorporated.

Mors Smitt developed a complete retrofit solution covering investigation, engineering, prototype production, testing, installation and commissioning. Several panel concepts using the existing mechanical mounting points were developed and evaluated, helping to demonstrate that the required relay functionality could be accommodated within the available space while simplifying installation.
Relays with integrated LED indicators were installed and grouped according to voltage. Two smaller panels were incorporated into the general panel, creating a more consolidated arrangement. Separate diodes and RC circuits were installed in dedicated Mors Smitt housings. Updated circuit diagrams documented the revised relay connections.
The prototype panels underwent visual inspection, functional testing and shock and vibration testing according to IEC 61373. Installation and commissioning were performed in cooperation with the customer. The intended project process also included two prototype trains followed by a three-month operational trial before the release of serial production. The resulting configuration provides renewed relay panels with updated functionality, improved component organisation and an increased safety level of SIL2.
Metro Rio – Brazil



Relays feature integrated LED indicators
Panels retain existing mechanical mountings
Smaller panels integrated into general panel
| Scope of Project DMRC | |
| Project scope | Retrofit of door and general relay panels |
| Panel types modernised | Door panel and general panel |
| Panels consolidated | 2 smaller panels integrated into general panel |
| Relay technology | Relays with integrated LED indicators |
| Safety level | SIL2 |
| Mechanical integration | Existing mounting points retained |
| Railway qualification | Shock and vibration testing according to IEC 61373 |
| Project activities | Design, testing, installation and commissioning |