Thanks for the kind words ! Yes that's the idea of the modules. I can for example just do the following
First, I didn't wanted to glue or screw the baseplates to keep them relatively reusable, so I used a bit of double sided tape, but it's not strong enough ; the baseplates tend to move when I assemble or disassemble the modules.
The connection between the modules is not very strong since it's only connected by the train tracks, so it doesn't work well on uneven surfaces.
You cannot take the modules appart in smaller pieces (think 32x32 baseplate size) which is not great to store or transport.
You cannot build "below" the baseplate level, for example to make a bridge crossing a river.
Those are only relatively small problems, but it was just annoying, so I took it all appart, started racking up bricks and plates, and will share the new modules soon
The layout on the sidings is basically an inglenook shunting puzzle. The initial plan used the idea from here : https://www.bricksmcgee.com/blog/lego-track-geometry/
When I was building the modules, I went with the layout aligned with the studs of the baseplates to make it easier to build, and because I didn't have enough DBG tiles to support the tracks on an angle.
On the next iteration, I think I will try the initial layout, it will look cooler, especially if I can put some decoration and some kind of warehouse on the same angle.