The air pump was, like the rest of the loco as I am finding, is different from the stuff that was available to me on the American parts loco. The air pump from the Bachmann Big Hauler is the closest for size, but to make it a decent model would take as much work as building from scratch. I had two choices, 3d design and print it, or make it. I chose to make since I could make it mostly for free from stuff I had laying around.

The first thing was to understand what I was trying to build. Of course I have David Fletcher’s drawing of it on the loco, but I needed to understand to how it worked so I could make sure I was putting things in place for a reason. Again David Fletcher’s Masterclasses to the rescue. The problem though is that his classes and almost all online resources refer to the second generation and up air pumps. There is very darned little on the internet about these pumps.

I started by building a pump based on Davids instructions, but modified to the sizes of the 6″ pump. It is taller and skinnier than the later pumps.

I didn’t have cylindrical plastic that was the correct diameter, so I accepted that it was going to be a little large. This is 1/2″ dia polystyrene.

I spent an hour looking for through my photos to fine one of the assembled air pump shown in the photo above. Then since I couldn’t find a photo I went looking for the actual piece to take a photo of it. I was rather disappointed with how it came out, so I must have tossed it. The pumped looked kind of sad because no matter how hard I tried to ensure that the center C shaped piece was square, it was not. The top leaned over looking kinda Bill from the School House Rock “I’m just a Bill”. Not that much, but enough that you could see it.

The second issue that led to it being tossed was that I did eventually find a drawing of the original 6″ pump and combined with photos of the real thing I found that it was not constructed the same as the later models.

This shows the mounting tabs and that ends of the cylinders where in line with cylinders. There where no flanges like the later ones.
Instead of starting a new plastic pump which would still have been too large in diameter, I turned steel parts. They are about 7/16″ diameter and with a hole drilled in a lathe and 1/16″ welding rod for the piston rod the pieces are perfectly lined up and all the correct sizes. The stripes around the cylinders is the heads at each of the cylinders.
Again following David Fletcher’s example in the Masterclass, I modeled the mounting brackets using the original drawing to figure out where and how they went. Above you see four strips of polystyrene shaped with rounded ends and taped the appropriate distance apart. The steel pump is then epoxied onto the strips.
Once the strips were hardened on, I made up the fittings using polystyrene tube and rod of various diameters. All parts are epoxied onto the steel
How to mount it to the boiler? The pump needs to stand out from the boiler to allow the reverse reach rod to pass behind it. I joined the four tabs on the back of the pump with angle. I decided where the mounting pins would go and drilled the holes. 1/16″ rod is used for support. I positioned the pump vertically according to the drawing and marked the angle pieces. I then made up 1/8″ tube pieces that fitted the curve of the boiler and were longer enough to hold the pump vertically and glued them to the angle material.
Painted and ready for final assembly.

Wow, time flys. I didn’t realize I had a half finished post sitting waiting to be posted until I finally had time to come here and look after my site. I last looked at this site back in May. Late spring hit and that was it. I was waiting for drivers to come in. That took forever. We were going camping, so I needed to get my vintage camper ready. Finally here I am four months later and I can devote some time to this.