Hi Olga, I guess I see that it is not quite right in this area:



But it looks really close in other areas.

I would think that you would use the same technique you used in this model, but put some additional profiles but try to make some adjustments.

Terminating the curve structure at the top should help to avoid the upper part kind of bulging out.

For example, instead of having the rails continue, cut them to make them stop at this location:



If I knew more about how you constructed this model it would make it easier to help.

Maybe I don't understand, but it looks like this is already close to what you are asking for, so I'd think you would want to use the same method you did here but make some adjustments.

- Michael