Example 1: Hornby Princess with sound, stay-alive, lights and smoke

Kit: MX645; IceCube28X18X10-2W; Seuthe #27; 4x 220uF Tantalums; 1 boiler door lamp; firebox glow

Here's our donor model, which is stunning to begin with...

In order to add the Seuthe smoke unit, we need to remove some of the plastic underneath the front chimney.

We also need to mill some off the front of the chassis, as the Seuthe unit will sit down in this area.

A tiny bit of filing is required to get the Seuthe #27 to slide snuggly up into that front chimney opening.

The unit is secured in with DevCon epoxy and left to set. Later, we tuck in the intended MX645 decoder to check that it will go in OK with the body back on - looks good.

The decoder will be hard-wired, and we add a few Tantalum capacitors for stay-alive - it doesn't need much since the model has all-round pickups anyway, but even a bit of backup power is useful.

The Tantalums sit down inside the gap in the chassis block, secured with some BlackTack and protected with Kapton tape. Not shown here, we also wire in a single lamp on the boiler door, and firebox glow, then refit the loco's body to test - we can test everything without the tender attached, except for sound of course (since the speaker will be in the tender).

The decoder is hard-wired in, splicing its' red and black pickup wires to the loco's pickups, and connecting orange and grey direct to the motor terminals. The 4-way connector to the tender remains intact, continuing to use 2 of those wires for pickups, but the other 2 (originally for motor) are now going to be used for the speaker instead.

In the tender, we grind down the screw mounts from where the 8pin DCC socket was, as this is where our dual IceCube speaker will sit.

This is wired in to what used to be the motor wires.

All done, back together and sounding/looking great!

Example 2: Streamlined Version, dual speakers

Kit: MX645 hard-wired in loco; IceCube18X13X09-1W; 4x 470uF Tall Tantalums; Seuthe #27; 2x Vertical Mount Yellow Lamps; Firebox Glow, YLR302815 or YLR603010 in tender

A little more ambitious for this stream-lined version, including 2 speakers - a small one in the nose and a bass box in the tender (2 different options there).

Here we see the chassis (completely disassembled) clamped into our milling machine to take off the chunk at the front where the Seuthe smoke generator will go down into.

The single IceCube speaker tucks up neatly right at the front.

A YLR302815 2W bass box speaker just fits into the tender (with the metal weights still in place), though a fair bit of plastic removal was required under the coal load to do this.

A new coal load is built, using scraps of card, BlackTack and lump coal to finish.

Please note that these guides are provided as useful resources for you, as-is. YouChoos cannot be held responsible for errors in the information, or for any damage caused to your models or equipment if you choose to follow any of the steps detailed here.