Abstract: To analyze the loading balance problem, the scalable coherent interface for real time(SCI/RT) TRAIN protocol was simulated by using OPNET . The results show that the incensement of the nodes throughput is quite different from each other, along with the ringlet load increasing. In case of the heavy ringlet load, the down stream nodes far from ticketmaster gained almost zero load, while the nodes near ticketmaster gained almost all the ringlet load. The SCI/RT TRAIN protocol gave the ticketmaster migration method to solve it. According to the simulations of a ringlet of 8 nodes, the ticketmaster migration method can distribute load between ringlet nodes but the performance of its function is very dependent on its configuration. When every node has the ticketmaster module, the method gets its best function. In this work, a new comparative method named extending sub-priority was proposed. It was proven that the extending sub-priority method gets better loading balance and higher node throughput than the previous ticketmaster migration method. On the other hand, based on the simulations of 6 nodes, 10 nodes and 12 nodes ringlets, the proposed extending sub-priority method was proven to be functional in ringlets with different scales.