Aristocraft U25 Dead Rail Protothrottle Install

I decided to document the install of a Protothrottle Dead Rail Receiver and Soundtraxx TSU-4400 DCC decoder into my Burlington Northern AristoCraft U25B. I picked up this locomotive a few years ago used. It was in really good shape with Kadee Couplers already installed. It was setup more or less stock for track power so it was a good candidate for a conversion. This is my second U25B, I really like these locomotives, nice looking but simple in design and lots of room inside.

So the basic idea here is to open it up and pull all the wiring, smoke generator and old style light bulbs. I am also going to inspect and lubricate the motor trucks and remove the track power pickups and wipers. Instead of track pickup, we can rewire things so the motor trucks get their power from the Soundtraxx decoder which will also drive the LEDs and the speaker. A 3.2ah Lipo Battery will give us plenty of driving power and it should all fit with room to spare.

First step is to disassemble everything. There are five or six main screws on the bottom that hold the shell and cab on. One is hidden by the fuel tank so you have to remove that first. This particular U25B had an ancient sound card in it so I removed that too. I also don’t like smoke, it’s greasy and gets all over everything and not really worth the mess and the power drain on the battery, so I pulled that out too.

The old sound card is shown on the lower left. On the lower right is a pic of the finished speaker box, it is a much bigger speaker with a heavy magnet, I forget the make, I think I got it out of one of those desktop computer sound systems I got for free from someone. It’s been sealed up to create a good bass and just does fit in the tank, although I did have to remove the weights and cut off two plastic stand off pieces. Sorry I don’t have better pictures of the speaker box, but it’s not real fancy, I just sealed it in with ‘goop’ (its a flexible plumbing cement) and added a sheet of polystyrene plastic on the top. It has to be airtight to get a good bass.

In the following pictures I’ve removed all the small circuit boards and wiring for the bulbs and sound unit from the main chassis plate. All that remains is the power connectors for the trucks.

Next pictures show removing the trucks so that I can open them up and take a look at their condition. I’ll also remove the electrical pickups and make sure the grease on the gears is still viable. What remains is just the two power leads to the motor on the trucks. This particular locomotive looked like it had been ‘played’ with a little bit- there were some splices on some of the wires so I fixed all that and put them back together.