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

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)

This guide shows how to convert the excellent Kato Class 373 'Eurostar' models to DCC, and includes motor and directional lighting control. There are two versions of this model which are exactly the same electronically: the original white and yellow version from the early nineties, and the dark blue version. Electra Rail also do vinyls that can be applied to convert the model into GNER livery they had when leased for Leeds-London services for a period.

Digitrax produce a swappable PCB for converting this model to DCC (DN163K0a), however it is expensive and still requires some modification to make it work. For example, it is supplied with two white LEDs (one of which is pointing in the wrong direction) so the original red LED needs removing and re-using from the stock PCB. Geoff at Flint Hills has described how to perform the DCC conversion using the Digitrax board. The steps shown there for converting the directional lighting in the dummy power car are incorrect and will not work as shown in the video. This is because as manufactured, the directional LEDs are fitted with opposite polarities.

This guide uses an ESU LokPilot 5 decoder, which is very small. The procedure for converting the power car and dummy car are broadly the same, with the exception that obviously you don't need to connect a motor in the dummy car.

Step 1 - Remove the body

Remove the body by gently prising upwards. Note that there is a thin piece of plastic trim on each side - the point to get your plastic pry tool in is just above that. Once the body has been popped off, these plastic pieces of trim can be removed by sliding them towards the back of the loco. Note the layout of the stock PCB - the red LED is at the front, and the white LED is right in the middle.

Step 2 - Remove PCB

To remove the PCB, gently remove the grey plastic clip just in front of the white LED. Bend the motor contacts up slightly to help it pop out.

Step 3 - Isolate Power Rails

As with many Kato models, there are two 'rails' that run the entire length of the unit to provide track power to any PCBs or sub-assemblies. These rails need to be isolated from the motor contacts. Pop them out by pushing the outer black clips holding them in place towards the middle. Remove the capacitor that bridges the two rails. Wrap some Kapton tape around the rails so that when the motor contacts are bent back, they cannot make an electrical connection.

Refit the rails.

Step 4 - Modify PCB

Cut the tracks on the PCB where indicated in green on the diagram. Use a multimeter to check there is no longer continuity between the two parts.

Solder the blue wire (common positive) from the decoder to one side of the resistor. Then solder a small blue link wire between the other side of the resistor and the leg of the LED as shown. Note that the diagram must be followed exactly, and that the PCBs for the motorized and dummy cars are not the same.

Solder the white (front light) and yellow (rear light) wires as shown.

Step 5 - Connect Track Power

Solder a red wire from the decoder to one of the power rails, and a black wire from the decoder to the other. It is possible to take power from the outer tracks on the PCB, but doing it this way is more reliable as it doesn't rely on having enough pressure on the contacts.

Step 6 - Connect Motor

Solder the orange and grey (motor) wires from the decoder to the motor tabs, and add some heatshrink sleeving to cover the join. Tidy up the wires, and add some kapton tape or heat shrink to the decoder to protect it.

Fit the decoder just behind the PCB.

Step 7 - Reassemble

Refit the body, remembering to slide the long thin plastic trim pieces on each side before clipping the main body back onto the chassis.

Step 8 - Convert Dummy Car Lighting

The process for converting the dummy car is broadly the same as for the powered one, except there is no motor to connect and there is much more space inside the body for the decoder.

Remove the body and PCB as above.

Route the blue and yellow wires through the centre of the empty motor harness so that the blue wire comes out through the centre circular hole, and the yellow one comes out to the left.

Step 9 - Fit Decoder

Follow the steps above for modifying the PCB, making sure you follow the correct diagram as the PCBs in either end are mirrored.

Solder the blue, yellow and white wires from the decoder to the PCB.

Step 10 - Connect Track Power

Solder the red and black wires from the decoder to the power rails.

Add some kapton tape or shrink sleeve to the decoder to protect it, and fit it in the gap at the back.

Step 11 - Refit Body

Refit the body and the conversion is complete.

Place the powered and dummy locos on your test track. Confirm that the loco runs in the correct direction, and that the directional lighting is correct for the direction of travel. If the loco runs in the wrong direction, simply reverse the orange and grey wires in the powered end. Alternatively, you can use CVV programming of your decoder to reverse the direction.

If the directional lights are reversed, i.e. the loco shows a red light at the front, and white at the rear, then you can either reverse the yellow and white wires in whichever end is affected, or you can use CVV programming to swap them round.