How to convert N Gauge Kato Eurostar (Class 373) to DCC Sound

This guide covers all versions of the Kato Eurostar model, which are identical other than the liveries applied:

• Class 373 e300 3201 Eurostar in original white/yellow/blue livery (10-327)
• Class 373 e300 3005 Eurostar in original white/yellow/blue livery (10-1295)
• Class 373 e300 3015/3016 Eurostar in post-2013 blue/grey livery (10-1297)

These are very difficult conversions which require removal of most of the factory electronics and track pickup arrangement. In the case of the motorized power car, sections of the chassis need milling out to provide space for the speaker and sound decoder.

It is possible to retain the original track pickup arrangement, i.e. the copper strips that run the length of the loco. However, these can be unreliable for DCC and it also makes more room if they are removed.

Step 1 - Dummy Driving Car

First remove the stock PCB, track pickup strips and (redundant) motor housing from the middle of the chassis.

In the large space that remains, glue the speaker and a Next18 decoder socket PCB. Solder two brown wires from the PCB to the speaker, and the red/black wires directly to the top of the bogie contacts at back. Run another red/black wire from the front bogie contacts and join them inside the rear section.

Solder a 1K resistor to the blue common positive wire. Solder two further blue wires to the other end of the resistor and then cover the whole thing in shrink sleeve.

Run one of the loose blue wires wit the white wire to the front. Glue a piece of plasticard to the top of the chassis. Solder the wires to a red LED. Bend the legs so the LED sits in the correct position, then glue to the plasticard.

Run the yellow and other loose blue wire to the middle. Again, glue a piece of plasticard to the top of ther chassis. Solder the wires to a warm white LED and bend the legs to get it in the correct position. Glue the LED to the plasticard.

Test that your wiring is sound using a multimeter, and then fit your Next18 decoder. Place on your test track and confirm that the lights and sound functions work correctly.

Step 2 - Motorized Driving Car

Remove the stock PCB and track pickup strips. Mill out the rear section of the chassis above the rear drive shaft. You need to remove as much material as possible without anything being able to foul the driveshaft or flywheel. You may wish to completely remove all components from the chassis to perform the milling to prevent accidentally damaging anything.

Mill out the back section of the chassis just above the rearmost wheelset. Glue a piece of plasticard to the bottom of the speaker, this will provide a keep for the coupling later. Glue the speaker to the back of the chassis.

Put some kapton tape over the milled area of chassis above the drive shaft. Glue a Next18 socket across the gap. Solder two brown wires from the socket to the speaker. Run red/black wires directly to the top of each bogie contact at the front/back as you did for the dummy car. Solder the red/black wires to the socket.

Cut down the longer (+) leg of a warm white LED. Solder a 1K resistor to the cut leg. Solder a blue wire to the other end of the resistor, which then goes to the decoder socket. Solder a white wire from the decoder socket to the other leg (-). Glue a piece of plasticard to the chassis. Bend the LED legs so it sits in the correct position, and then glue the legs to the plasticard.

Cut down the longer (+) leg of a red LED. Again, solder a 1K resistor to the cut leg. Solder a blue wire to the other end of the resistor, which then goes to the other LED positive blue leg. Solder a yellow wire from the decoder socker to the other leg (-). Glue a piece of plasticard to the chassis. Bend the LED legs so it sits in the correct position, and then glue the legs to the plasticard.

Solder grey/orange wires from the decoder socket to the motor contacts. Add some shrink sleeving to the joins.

Finally, test that your wiring is all correct using a multimeter, before fitting and testing with a Next18 decoder. Place on your test track