Similar issue when trying to isolate my solar /accu field by cutting the last copper wire/removing last connecting power pole.
The field is however still connected by a Main power switch to the factory (marked on the map, north of the solar field).

The map was made in 0.14

Yes it is in the most recent 0.14 experimental update. And ok, will just have to keep this in mind when planning rails

Hello As you can see in the following two pictures, depending on the direction of the signaling, the same distance between rail signals lead to different allowed cargo length. This is somewhat annoying and would require to extend the "bottom to top" rails to be able to fit the same amount ...