The Hornby Class 56 is typical of most Hornby diesel and electric models in that it's not DCC-Ready but it's a fairly easy job to hard-wire a decoder using a soldering iron. The Class 56 tooling was originally owned by Mainline and then Dapol, so these instructions are equally applicable to those versions. The model has remained almost unchanged throughout it's history.
Of course, there are many ways to convert locos and we all have our own preferences, these are merely mine, offered in the hope that they might help someone, somewhere make a start. For example, you can solder the decoder leads directly to the motor terminals - I just prefer a central mounting point as it makes later alterations to things such as the lighting circuits that little bit easier. Decoders, too, are an area where tastes will vary, but the one suggested here is a reliable performer and well matched to the loco. It's a good place to start if you haven't already developed your own opinions, I've converted all of my Mainline, Dapol and Hornby Class 56 fleet using them.
Photo 1
All you need. The loco, a small piece of circuit board, a decoder (in this case the Lenz LE1025E) and the double-sided sticky pad supplied with it. Also you'll need your soldering outfit and a craft knife or wire stripper (not pictured because they're not very photogenic) along with a cross-head screwdriver - not pictured because I forgot. If your loco is brand new like this one then it's probably a good idea to test-run it before proceeding in order to check everything is OK.
Note that although I've used a plug-fitted Lenz LE1025E decoder here, the plug isn't really required - it was all I had to hand so I just chopped the plug off and used it as I would the wires-only version, the Lenz LE1025A.
Photo 2
Most Hornby locos have bodies that clip onto the chassis, and this one is no exception. There are four clips at the bases of the cab doors which need to be released, if you have difficulties then wedge a piece of card in the gap to stop them popping back into place.
Photo 3
With the body off and the innards laid bare, you can begin to see where things need to go. Current Hornby production has easily visible terminals for everything and no hidden pitfalls such as screws that need to be isolated. Everything is ideal for attaching a decoder to.
Photo 4
Because of it's Mainline parentage, the Class 56 is assembled in a slightly different fashion to most of the Hornby range. To get the power bogie out easily you need to remove the screw seen in the photo...
Photo 5
...which allows a small, black plastic bar to come away and the power bogie to drop out through the chassis frame. Unsolder the orange capacitor, the wires and any other gubbins clinging to the bogie. Throw the capacitor in the bin as it hinders DCC operation. Also discard the light bulbs and related wiring. I prefer to fit replacement lighting, using either LEDs or the kits from Express Models but I'm not going to cover that here - this is just about fitting a decoder.
Photo 6
Solder an orange and a grey wire to the motor terminals as shown in the photo, the orange one towards the top. Also solder a length of red wire to the pick-ups on the bogie side.
Photo 7
Replace the power bogie in the chassis frame, feeding the wires through first, and secure it in place with the screw and the black plastic bar.
Photo 8
Next solder your red orange and grey wires to a piece of stripboard (product code FL17T from Maplin) making sure each wire goes to a separate track. Also solder the black and red wires from the other bogie as shown, the black one to a new track and the red one to the same track you soldered the first red wire to. Stick the stripboard to the top of the weight with a double-sided sticky pad - one piece of stripboard will do many installations if you cut it into 9-strip chunks as I've done here.
Photo 9
The final wiring operation is to solder all nine wires from the decoder to the stripboard. The red, black, orange and grey wires need to match the corresponding colours from the bogies, but the remaining wires can be soldered to any other free strip. These wires can power lights if you wish, but aren't used here as we're just concerned with the motor. Hopefully the photograph will make this clearer. Fix the decoder to the weight using a double-sided sticky pad, you might want to trim the wires a little to keep this neat.
Photo 10
Before putting the body back on the chassis it's as well to check that everything is working. The safest way to do this is to put the loco on the programming track and try and read information from the decoder - the instructions for your particular DCC system will tell you how to do this. If all is well (and I've never yet had a problem) then clip the body back on, making sure the circular grilles in the roof are above the power bogie.