How did the LEGO 7862 Remote Controlled Decoupling and Signal work? I've never seen this set in person, although it appears occasionally in 12V Lego train system images. I've never seen it used, or described.

How did the LEGO 7862 Remote Controlled Decoupling and Signal 12V work? What is the 'Signal' component of the decoupler?
It basically forces the coupling magnets to separate via the pins pointing downwards from the magnet holders:





Here's a demo.