[English is a second language for me.]
Hi ! Maybe I'm missing something, but I'm not able to use the vehicule roboport. I'm currently trying it in a train (locomotive & cargo wagon).

In the ''grid tab'', I have a vehicule roboport an a portable generator loaded with solid fuel. The vehicule roboport has electricity. I can't add construction robot in the ''grid tab'' and it's not working when I add them in the ''inventory tab'' of the cargo wagon. I also tried using it in the locomotive. I'm probably doing it wrong but I can't figure it out.

Thanks a lot and have a good day !

Hello! Place the roboport and generators in the "grid" tab. Make sure that generators are working. Then place drones in the car/vagon inventory. Now they have to work. Video with demonstration:
https://drive.google.com/open?id=1ptVGMFbKxpOrW_sG3dkFPSF25LVEuflX

Thanks a lot for the video ! I was trying to build with them, that's why it wasn't working. Deconstruction works perfectly !

For the construction you need to put all the materials/items in the trunk of the wagon/car =)