Very interesting idea!

Can the tank snake eat another tanks to grow up?

I was thinking of adding a mechanic where "eating" biter bases would heal the snake tank, but I wanted to get this out before I got busy with other stuff so I just didn't have time.

But, putting component pieces in the snake head's trunk will allow it to consume them to replace lost pieces.

Earlier I have done the Land Trains mod, but the problem was between links: the distance between wagons was bigger by high speed than before, the connection works like a rubber. How are you solve it?

Speed of the consist's elements is proportional to distance. There's still a bit of a rubberband effect, but I think it's OK for a snake-like thing.

segment.speed = math.max((distance-1) * speed,speed/4)

So when an element is 2 tiles away, it's moving at 100% speed. If it's more than 2 tiles away, it will go faster to catch up.