Train on SL waiting for a large enough gap in ML traffic: Prio sees a gap in ML large enough to fit a train into, gives train on SL the green light: Train on SL uses acceleration track (track between the entry presignal at A and the actual merge at B) to get to full speed (87 mph is wagon speed limit): Actual merge into ML occurs with the train at full speed: Merge complete:

The distance between A and B will have to be tuned for the traffic merging onto the ML at each location. Trains with different weights or speed limits will need separate joiners.