Having read a great number of twins threads I "think" I may have a handle on the concept but still a certain ,"uncertainty " remains so I hope you will bear with ONE more space voyage. Hopefully it is a simple one. There are two space stations at rest in freespace near Earth and Alpha C ,,,, E (St) and A (St) respectively , that have synched their clocks/calenders. Two Spaceships E shp and A shp that are traveling at the same relativistic velocity on a course for E (St) by way of A (St) and are spatially separated by the same distance as the stations. They also have synched the clocks in their frame and they are physically identical to the stations clocks. As E shp passes A St they exchange bursts of info. The ships current time and the current A station time = Earth time in E-A frame. They also send the info to E St and A shp allowing them to calculate the start time of the journey when they receive the transmissions. Upon reaching Est and Ast respectively they once again exchange info in passing with NO acceleration in the entire journey. So my question is: Am I correct in assuming that E ship and Earth station would agree on the elapsed time as measured by clocks in their respective frames? NO net time dilation effects??? Likewise for A shp and A sta.?? That their world lines as drawn by either frame would be equivilent??