Question about starting point for rail tracks

[Zapha]

Is it impossible to start rail tracks placed on roofplates?

Because that's my impression after I made first steps with the new DLC. Around my base in the mountains it's impossible to place tracks on the ground. Therefore I placed the first track part on roofplates on my base and tried everything to extend the track. Not possible.

I made a test at another flat place area with roofplates slightly above the ground, and placed the first part on them. Same result, impossible to extend the track alltough it has contact with the ground. If I place the first part on the ground everything works fine.