This is an example of how DCC sound can be easily added to a Hornby OO scale Thomas the Tank Engine model using a Zimo MX648 sound decoder and 12mm height Zimo sugar-cube speaker. This example also adds firebox glow.

Here's the cheery little fellow, unsuspecting...

Jumping now straight to the point where the MX648 and sugar-cube are already installed. There is plenty of space on the downward-pointing motor to stick the decoder, and the 12mm height Zimo sugar-cube speaker sits very happily at the front of the chassis, mounted on a thick super-sticky double-sided pad.

We've removed the factory capacitors across the motor terminals, as these are not required under DCC running. The decoder's BLACK and RED wires are soldered to the pickups on either side. The decoder's ORANGE and GREY are soldered to the motor terminals. Nice and simple!

Excess function output wires have been removed completely from the decoder, but there is plenty of space if you prefer to trim and insulate them instead. We've kept only the BLUE and GREEN function wires, as these will be used to attach a firebox glow light.

A quick drill of a 3mm hole through into the cab area - roughly where the firebox is located, then hollow it out a little with a Dremel (this helps increase the visibility of the orange light in the cab). Positive side of the SMD LED has a 1k resistor added, then joins to the decoder's BLUE (common positive). Negative side of the LED goes directly to the decoder's GREEN wire. Superglue to fix the LED in place behind the hole. Heat shrink to protect, electrical tape to protect the back of the LED from shorts, and to stop any light from dispersing inside the body!

Finally, we add some lumps of lead to the sides, and a lump behind Thomas' face, to improve traction and pickup - well worth doing when there is so much spare space available in this model!

All done, reassembled, tested, and here showing the firebox glow shining away.

Peep peep!

YouChoos can supply an MX648 loaded with 3F Jinty Tank sounds. However, if you have your own recordings that you would like us to include on the decoder, then you can make this quite a fun Thomas model!

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.