Installation of Airwire G3 in AristoCraft U25B

With the successful conversion of my NW2 complete, it was time to move on to BN 5406, my AristoCraft U25B. The decoder I installed was an AirWire G3 which is their generic decoder for use on most locomotives that are not manufactured by USA Trains. Unlike the NW2 install where I was following an instruction manual designed specifically for that locomotive, here it was up to me to figure out exactly what to do and where and how to install the decoder card. Fortunately my previous installation gave me the confidence that I could do it.

Removing the existing wiring was straightforward and I found it especially satisfying to disconnect the power pickup leads, given how much trouble I had with them earlier. I kept the original switches behind the back door so I could use one of them as an on/off switch. I also removed the smoke generator as I wasn't using it, it appeared the blower fan was no longer working, and it was taking up space that I wanted to free up.

The most difficult part was figuring out how to mount the board. Unlike the board for my NW2, this one didn't have any holes for mounting screws. And the board was so small and tightly packed that I couldn't see any safe place to drill holes. The instruction manual suggests somehow mounting the board vertically to allow air flow, but this locomotive doesn't have enough vertical clearance to allow that. I didn't want to lay it flat on the floor either, so I decided to build brackets that would hold it above the floor at an angle so it would still get some air circulation. I don't know if this is the best solution but I think it will do for now.

Both locomotives are now operational on battery power and I've done some testing inside, but I need to get outside once we have some nice weather and do some real world testing. I'll be able to operate both of them from the same remote control and should be able to operate them in tandem as a consist. I also want to do load testing and see how much they can pull now.

A view of the as-is wiring, some of which was original and some of it modified by the previous owner.

After removing most of the existing wiring I decided on a location for the decoder.

The decoder after wires were attached. The blue/green wire pairs provide power to the trucks. The red/black pair on the left disappearing through the floor is the power cable that will connect with the battery car. And the other wires in the upper right go to the front cab/headlight/number board and to the rear headlight/number board.

Since I had to dismantle the cab anyway, I took the opportunity to clean the interior so the locomotive engineer will stop complaining about all the dust.

When I was testing I noticed the interior cab light was working but the headlight was not. There was some corrosion around the wire connectors so I cleaned it up and replaced some of the wire.

Cab reassembled and mounted back in place.

A happy engineer with a clean cab and a working headlight.

Solution I came up with to hold the decoder in place, at least for now. We'll see how well this works.