So the prints by the circular train are simultaneous in SF, but the prints by the single wagon are not simultaneous in SF.Simultaneously in the moving frame (MF).
RS: From the full story: "Every printer has a clock that is synchronized when the train is at rest and thereafter the train is accelerated to a constant velocity v. Thus all clocks are accelerated in the same way and so all clocks will develop the same deviation in relation to SF. So all clocks will still be synchronized in RS when the train is at speed."
The issue here is not angular vs. linear motion.When the angular and linear motion smoothly transform to each other in the limit, should not the distances between the dots do as well?
The issue is that the wagons of the circular train are forced to keep a constant length in SF, so their clocks stay synchronized in SF. Your single wagon is not forced to keep a constant length in SF, so its clocks would desynchronize during acceleration in SF. If you setup your single wagon just like your train wagons (including forced constant length during acceleration) it will print the same dot distances as the train.