I'm still working on those diesel rebuilds, but they're nearly done now. After figuring out that the headlight LEDs could be wired back-to-back, I'm on to the next phase. The LEDs look great; I've got one each for the upper / lower headlights, and only one comes on depending on which direction the loco is facing on the track. I ended up using 1.2k resistors, and the brightness looks about right to me. Track voltage w/ my Keller Onboard system is 14.5v DC. I mounted the LEDs by soldering a pair back-to-back w/ the right spacing (to match the headlights on the shell), filing the end of each LED flat, and super-gluing them to the rear of the headlight lens.
With the headlights done at last, I moved on to connecting the A- and B-units, installing the Keller decoders (called throttles actually) in the B-units, and routing some small stranded wires between the two units. On the F units, I mounted Kadee #47s (I think - short shank, underset, metal) couplers, and was able to run a wire thru each of the ear holes on the Kadee boxes. I used shrink-tubing to attach a second wire to each of these, and thus got four wires routed alongside the coupler boxes, looking almost like MU cables. Two wires carry motor power from the decoder in the B-unit, and two carry track power to the decoder.
What's left? Final details on the shells, and (probably later on ) weathering. Air brushing is another long-dormant skill, so I'll have to get back up to speed there as well. But with 4 new Keller-equipped locos, I'll probably focus next on getting Keller installed on the layout, so I can use these new guys.
I've also finally posted a newer version of the layout trackplan. I had created a design in Empire Express for another friend, and a fringe benefit of that is that I really learned how to dress up the drawing within that software package. What do you think?