The diagnostic team shall carefully review geometric configurations with multiple crossing approaches to provide queue prevention or queue clearance at each crossing location. Figure 3-5, illustrates a scenario where a track crosses two legs of a single intersection. Special consideration for a pre-signal or queue cutter signal to provide queue prevention is important where queues are likely at both crossings.

If interconnection will be provided from each crossing location, one leg should first be cleared and the railroad warning devices activated to restrict additional vehicles proceeding over that grade crossing. For the TxDOT standard railroad preemption interface, the track clearance for the first leg should be terminated by a pseudo gate down timer (See Chapter 5, Section 3 related to active-style interfaces). The second approach should then be cleared and the railroad warning devices for the second crossing activated to restrict additional vehicles proceeding over that grade crossing. This can require substantial preemption time from the railroad and may not be feasible given railroad equipment limitations. The diagnostic team should review potential queue prevention for this geometric configuration.