Here a thread about the "Mobile Crane". I bought that machine as a second hand from a UK shop.
It's a mix of the LGB Diesel D10 (2090) and the LGB crane 4042.
The chassis is hand made, probably some ABS and nicely glued. The join for the glue looks like, it 's a glue that weld the ABS together.
There 's a small piece crafted to cover the hole from the cabin.
The engine are from LGB diesel 2051 (2051 I and 205 II). It fit very well the crane and diesel design.
There 's a line of of copper under the chassis from one end to the other end, and the ligth are linked to it.
The copper line is probably coated with a layer of varnish, no sign of decay.
The light system reverse as well.
I remove the coupler for the moment as it cannot handle R1 curve. The front buffer is missing need to be glued again.
Here the pictures :