from were you are up to:


I am not sure as to how you got to this stage with the model, but if we look at the curves you have used for the doorways/ windows there are some problems.



if we look at the top of the doorway where you have used those curves to trim the surface, then zoom in to where I have highlighted




you can see there are problems with the edges produced. this will then cause more problems when attempting further work




So, lets move back.
I have taken the main skin of the train and then made an offset surface



When drawing the curves for the arch at the top of the doorway I have made sure that the curves align (basically the same as we looked at before) for the bottom of the doorway I used fillet.



Ithen used those curves to trim away the doorway.

For the windows, I just made 3 lines to get the shape I want



Then selecting 2 of those lines I used "fillet" and just used a size that looked ok for the example. I then select the 2 lines that made the other corner, and again used fillet.



I then used those lines to cut out the windows. (I have hidden the door/window cutouts to show better)




Now, to fill the gap between the 2 surfaces.

First select one of the surfaces and then select all the edges of the surface that make up the opening of the door/window. Once all selected,press "Join", this will in fact copy those edges, paste them back and join them, repeat tis for the other surface.





When done, select both of those curves that have been created and select "loft" which will create the surface needed.




sorry for the long delay in my replies, I have a lot on at the moment.


Regards,

- Steve