Originally Posted by Chevalr1c
The problem is that at or near the max cart speed (8 m/s), the connection starts to lag. Main issue seems to be the fact that the loading of the section of the world one is in did not even (or barely) finish loading before leaving it. So at ~8 m/s there is too little time for the system too load. Hence the stopping train service (assuming you know what a "stopping train" is, some rail corporations call them "sprinters") because this will smoothen the ride (as a whole) quite a lot, and also gives players opportunities to get refreshments at or near the in-between stations if they need to (not yet organised).
But maybe the physical move of the server helps (more bandwidth), as well as leaving off BOINC (I will try again soon).
all i know is i used high speed rails on my server for long striaght-aways and the speed went well above ~8m/s. I rarely saw lag. there may have been something in the coding or another plugin that prevented it.