This is an early Atlas loco. It doesn't even have flywheels but runs very well. It also has traction tires so pulls well too. Although the top speed is rather high but this can be overcome with decoder settings.

This is a relatively easy install as there is very minor frame modification and there is quite a bit of space between the top of the frame and the shell.

As you can see we will have to file down the frame slightly as can be seen in the photo below.

I found that this was all the filing that was required and I could feed the wires down to the motor no problems as the gap between the frame halves was sufficient. However, if you are having trouble feeding the wires file off the tab marked in black(to the left of the grey oval) in the picture below

Modifications to the motor pickup tabs are simple. Just trim them back to the edge of the motor. See the before and after shot below.

As you can also see in the photo I have filed a small groove in the motor to locate the orange wire.

A note on soldering the wires to the motor tabs:
I solder to the tabs with the brushes etc still installed in the motor. Now, this has to be done very quickly otherwise you run the risk of melting the plastic on the motor and goodbye motor.
If you are not comfortable with your soldering then I would recommend removing the brushes and tabs from the motor before soldering, becareful not to loose the little springs inside.

Wiring in the lightboards is pretty standard but here are a couple of pictures to show where the wires go

Front Lightboard

Rear lightboard

That's all there is to it really. Here is the completed install and it runs great.

Note:- Since doing this install TCS has brought out their CN line of decoders and they are really easy to install in this loco. All that has to be done is isolate the motor, solder the wires to the motor and replace the light boards with the CN decoder.