Installing DCC into the Kato N RDC


Kato USA make a number of N-scale (1:160) models of the Budd RDC (Rail Diesel Car). These models are released mostly in matching pairs and cover four of the five types of RDC - the all-passenger RDC-1, the baggage/passenger combination RDC-2, the baggage/Travelling Post Office/passenger RDC-3 and the shorter baggage/Travelling Post Office only RDC-4. Kato USA have released them in a wide range of both US and Canadian roadnames, although surprisingly they did not include either BCRail or VIA Canada, both of whom where still operating the units in mainline service at the time of release of the model. The RDCs modified in this way were purchased from Hockley Valley Railroad (Orangeville, near Toronto ON, Canada) and America's Best Train Shoppe (near O'Hare airport, Chicago IL, USA). Both these stores provided excellent service and I would recommend them - consult their respective web sites or email them for latest prices and availability. The Digitrax DN122K2 decoders fitted to these came from Allied Model Trains (Culver City (near LAX Airport), Los Angeles CA, USA), Des Plaines Hobbies (near O'Hare airport, Chicago IL, USA) and America's Best Train Shoppe (again near O'Hare airport, Chicago IL, USA). Any impression that I regularly visit train shops in close proximity to major international airports is not entirely inaccurate.....

This web document is designed to explain how to install DCC into these locomotives (aka self-powered vehicles). The Digitrax DN122K2 has been designed to fit effectively into the Kato RDCs, but the modification as described in the supplied paper instructions, while simple, does not leave the resultant locomotive as tidy as one might wish - wires remain visible through the windows. The modification detailed here requires more work than the Digitrax instructions, but produces what I think is a more pleasing result since the cables are all obscured. It will take between 2 and 3 hours and requires the use of:

In addition you will need the following supplies for each RDC locomotive to be modified: This document is based upon instructions provided by Digitrax with the Decoders, with additional work by me.

DISCLAIMER: This modification is hard. You can damage your new model VERY EASILY with the tools needed to perform the modification. These instructions are designed to make the process easier, and are based upon the successful modification of no less than seven Kato RDC models. However we can accept no liability for what happens to your model, nor do we guarantee that this modification will work. If you undertake the modification detailed here, you do so entirely at your own risk.


Step 0: Unpack the loco and check it runs OK on analogue (DC) power.
There's no point in modifying a faulty loco!

Step 1: Remove the body shell.
The body shell does come off the RDC reasonably easy, but there is a bit of a trick to it. First slide your fingernails in between the chassis and the body shell along either side to make sure it isn't sticking. Then gently prise the body from the chassis, starting at one end - often gentle pressure to the area below the coupler can encourage the shell to come loose, but you do need to be gentle. Just tease it repeatedly and it will move. Once one end is off, you can hold the chassis on either side and pull the chassis and shell gently apart.

Step 2: Remove the light boards at either end.
The existing lightboards need to be removed and they are merely held by a small clip (which is part of the steps) at their side. Again gently teasing with a fingernail will free the board from these clips. Repeat the action at the other end of the car.

Step 3: Remove the white clip holding the motor contacts.
In the standard DC version, the two brass contact strips from the locomotive are held firmly in place by a shiny white plastic clip about mid-way down the body - this clip passes through the biege (and not so shiny) plastic molding of the seat backs. In DCC, we will not actually be using this clip again since there's the whole decoder between the pickup rails and the motor. I usually remove it by levering it up with a small flat bladed jewellers screwdriver - this usually propells it across the room, but since we won't be needing it...

Step 4: Remove the Under-Body detail molding.
The under-body detail molding (battery boxes, motor housing, etc) also needs to come off. This is secured by two clips on each side near it's end (ie by the trucks). Gently squeezing it at the sides, near the ends, should release at least one of these clips. Once released, the others follow fairly easily.

Step 5: Remove the seat-back/interior detail molding.
The trick to this is to first free the clips next to the drive shafts either side of the motors, from the underneath by using the jewellers screw-driver. These clips are pretty vital to the strength and good working of the model and you REALLY don't want to break them off. The clip ends extend outwards from the centre, making contact with the chassis. With the tip of the screw driver, gently push each one in turn a little towards the drive shaft. Each one can be freed in turn, and once done, you can turn the chassis back the right way up, and the four clips (two at each end) easily come off to free the entire seat-back/interior detail molding. Make sure you catch the four short brass contact strips that will fall out at this point. At this point you can also remove the biege plastic insert in the cavity into which the DCC decoder will be installed.

Step 6: Remove the Trucks (bogies) and Drive Shafts.
At this point you need to remove the trucks (or bogies as we call them in the UK) and the drive shafts. This is actually fairly simple - grip the bogies and turn them as if going around an extremely tight radius curve. At the extremity of the turn, give them a gentle tug away from the chassis and they should come off easily. Repeat for both ends; make sure you don't loose the drive shafts if those become detached from the trucks in the process.

Step 7: Remove the Truck Mount/Steps Assemblies.
The penultimate part of dis-assembly is to remove the two black plastic extensions to the metal chassis that support the trucks, couplers, end-beam and steps. Simply slipping a fingernail in to part the plastic clip from the metal toe is usually enough to free these. Repeat for both ends.

Step 8: Pull the motor out.
Pull the motor out. If it's reticent to come, a gentle push from below to the drive shaft ends is usual more than sufficient. Once this is done, we're ready to move on to making the appropriate trenches in the chassis for the decoder wires to be run under the interior detail molding.

...but that is a horror for another day...