The battery and sound board were installed in the fuel tank, along with a sliding on/off switch and the charging jack. This is a tight fit, but everything went into place.. I installed the remote volume switch on the rear underside of the locomotive. Wires from the speaker and the remote volume switch were run through a hole in the floor to the battery box.
To put the body shell back together, I built a small hook out of wire. This allows me to pull the sides out on the body shell without breaking off any detail when re-installing.
All wires were hooked up and the body shell was re-installed. The fuel tank was left unattached and the loco was put on rollers to set the sound options according to Sierra's instruction manual.
A reed switch was attached to the right bottom of the fuel tank to control the horn
And the fuel tank was re-attached to the bottom of the locomotive.