For HO-size decoders, with our PC harness, the decoder is placed to the side of the flywheel on its side edge, as shown in the photo at right. The decoder won't fit in back because that's where Kato has the speaker enclosure if you choose to install sound. The decoder could fit in back, with our PJ harness, if you don't mind hacking the enclosure out.

For Z- and micro-size decoders, with our PH harness, the wires are folded back so the decoder lies on top of the NMRA plug, as shown in the photo at right.