Hereby some pictures to make clear how the side beams are connected and constructed.
By taking out two pins on the front of the upper structure you can pull the sides outwards.

Then you can pull the side to the back so it comes of a black 3l pin.
You can now look inside the body and make adjustments

The side beams interlock with the main body on some points to give it some extra strength.
The A-Frame is connected to the main body, so no hassle with unreeving the wires if you want to change the colours of the crane.
The outside then looks like this.

In this way it is very easy to change the colours of the crane and the power is transported horizontaly through the side beams.
As said, on the front the boom is connected to these beams and in the back the counterweight is hanging from it.
More to come on the crawlers later this weekend.
Greetz,
As