This is a picture of the N scale car and the finished HON30 gondola.
I first cut the sides from the N scale car, which is the only thing I used from the original car. I built the underframe from brass so the car would have enough weight, and the ends were built from styrene shapes.
I scraped off the N scale details, leaving the rivets, and added grab irons, stirrups along with under body brake detail. I used N scale Arch Bar trucks as they are reasonable for HON30. Since I finished these cars, I have obtained some Grandt Line Gilpin Tram HON30 trucks and will be using them on future projects. This car ended up weighing in at 1.3 oz, so maybe I should find some brass trucks.NEXT: the TANK CAR
Starting with this N scale car, I took it apart and built....
J&N #2
These are the parts I used to build the basic car. After drilling out the riveted on trucks, the car comes apart easily with a single screw. The frame of the N scale car was too small for HON30 and way to light. I needed to add weight and size to frame and tried out several ideas including brass, styrene and wood.
The tank had slots in it, and I trimmed wood to fit in those slots to be chocks to hold the tank on the flat car.
I trimmed, filed and sanded all the molded on details except the rivets. 
I carved off the original dome and added a piece of 3/8" tube for the man-way. I also turned some steel bar stock I had laying around to fit in the tank for added weight. Even with all this added weight, finished, it only weighted in at 1.4 oz.
I finished off the top of the man way with..., you guess what I used.
To add maximum weight, epoxied brass bars in slots in the underframe. I decided to epoxy styrene all around the underframe to give me a 7' width and a reasonable looking length.
Here is the bottom of the underframe with the styrene added and the cast on moulding marks removed.
I filed the top side flat so the wood deck would fit tight.
I glued scribed wood to the underframe and trimmed to fit.
I painted the car, added a brake wheel, couplers and decals.
Then a little weathering and dullcoat for a finished look.#3, a FLAT CAR
I used the underframe left over from the gondola and some other parts to make
this.
The frame would be too light unless weight was added. I soldered brass bar stock to the sides and ends to give me the needed weight, width and length.
It took a while, even with a 200 watt soldering gun.
I filed the top flat and glued boards to make the deck. 
I stained the deck using the Pat Harriman method; I used Prismacolor markers.
I have gotta quit spending some much item on detail you can only see when the car is upside down! I used Grandt Line under body brake detail and stake pockets.
I did not figure the stake pockets into the width, so the car ended up about 6" wider than I would have liked, but I do like the way it turned out. This car weighs in at 1.5 oz. Considering it is about 4" long, that's not bad for a flat car.I have dozens of projects that are waiting on good weather so I can paint. I have primed several projects, but I will have to wait until the weather warms up to do the finish painting.
