The S pin goes high and low to five LEDs. The middle pin is +5V and the B pin is ground. You can use these to drive LEDs.
Here is the typical circuit, one LED will be lit at a time.
|Tender shell removed|
|34 x 14 Insulator|
Note the blue tack to secure the DCC hardware
|Speaker ready for final assembly|
Blue tack to the floor
|Parallel wired speakers|
|Series wired speakers|