The TCS A4X is a four-function HO-scale "drop-in" DCC mobile decoder for popular Atlas, Athearn, and Kato diesels — a clean, no-solder upgrade on supported models. Examples include the Athearn F59PHI and F3; Atlas RS-1, RS-3, RS-11, C424, and GP7; and the Kato GP35. If you need more than four functions or plan to run 1.5V bulbs, step up to the A6X.
Browse more DCC Decoders and DCC Accessories, or shop the full Train Control Systems lineup.
Will it fit my locomotive?
The A4X drops into many Atlas, Athearn, and Kato HO diesels (for example Athearn F59PHI/F3; Atlas RS-1/RS-3/RS-11/C424/GP7; Kato GP35). Check the TCS drop-in chart for your model.
Does it include sound?
No — it is a motor and function (mobile) decoder. For sound, see the TCS WOW series.
A4X or A6X?
The A4X covers four-function installs; choose the A6X if you need six functions or the 1.5V bulb supply.
