Have a set of older Stewart Hobby F 3 Kato Drive ? Wondering what decoder to install as it must be wired in.
I like to use lightboard replacement ones, like ones made to replace Atlas diesel's lightboards. There isn't much room between the top of the chassis/weight and the inside of the roof, so the lightboard fits nicely whereas a regular 9-pin "hardwire" one can be a bit of a tight squeeze.
That is one of the most common DCC installations that I have done. I prefer the NCE DA-SR, Digitrax DH163KO or DH163A0. These replace the existing circuit board. The DH163K0 already has the stiff power feeder wires installed. On the other two one has to solder stiff feeder wires in.
Using one of these decoders the installation shouldn't take more than 30 minutes.
As with most installations the hardest part is the headlamp(s). If you use the stock "light" tube be certain the bulbs wires are insulated so they don't short through the tube itself. I always abandon the stock tube and put in wires to 1.5V mounted on the back of the lens. Sometimes I add a small plug to make it easier to completely remove the shell from the drive.