That movement may have occurred for a number of reasons ranging from testing the recently completed movable structure to launch preparations. Besides the fact that the general low level of activity throughout the facility suggests a launch is not going to occur over the next few weeks, in the case of a possible October launch, it is probably still too soon to move the SLV to the gantry.
Construction activity at the Sohae Satellite Launching Station (“Tongchang-ri”) since spring 2015 has made it more difficult to spot launch preparations. Nevertheless, there are indicators likely to be present a few weeks before a launch that such preparations are underway, such as a significant increase in fuel loading and pressure testing activity at the fuel and oxidizer buildings. Moreover, it may also be possible to spot the SLV itself at the gantry.
Recent imagery also shows construction at the vertical engine test stand that will allow the testing of larger, more capable rocket engines is proceeding rapidly. That work, however, is unrelated to the question of whether the North will conduct a new launch in the near future.
