I really enjoyed building these three flat cars. The cars weigh 2.8oz (80g) each. That is about half of what they should weigh, but they appear to be tracking fine. I am going to add loads to them, so that will add some more weight.
Building three at a time actually was a really good idea. It doesn't really take that much longer to do three than it does to do one. As I gained experience doing a certain step on the first car, it was just that much easier to repeat that step on the other two cars. On the other hand, doing more than three at a time might make it feel more like a chore, and I might run out of set-up space in my confined quarters.
One of the cars' side sills didn't come out right (the styrene warped as I cut it out of the sheet). I should have just chucked them at the beginning, but I continued on with them. That had an impact on virtually everything I did afterwards, so that was a lesson learned. The center sill of that car isn't quite centered, so it has a hard time coupling with other cars sometimes. It looks like it was in a crash or got hit on the side during a load. I plan on building more of these cars in the future, and so I may "retire" that car as a scenic element instead of an operational car.
This was my second attempt at scratch-building a car. What I learned about myself was that I actually really enjoy these projects. I have also learned a lot about scratch-building cars in general, so my skills are getting better. None of the four cars I have built to date are worthy of contests, but they have been great training tools.
One of the decisions that I made while building these cars was that from now on, unless I am interested in building a contest car, I am going to skip all those items and details that are not visible when the car is operating on the layout (e.g. the underbody brake system). And I won't add the details that are going to interfere in the operation of the car (e.g. the Carmer release levers).