The Requestor shall collect applicable railroad warning times, existing advance preemption time, train speed, light flashing time before gate descent, gate descent time, buffer time, and railroad equipment response time from the Railroad. The understanding of these times will help the Requestor understand how the grade crossing will operate during a preemption event.

TxDOT Form 2304 automatically calculates the following railroad timing parameters:

Required Minimum Time (MT)
: The TxDOT Form provides the least amount of time active warning devices shall operate prior to the arrival of a train at a highway-rail grade crossing. Per TMUTCD, “Flashing-light signals shall operate for at least 20 seconds before the arrival of any rail traffic.”
Clearance Time (CT)
: The additional time that may be provided by the railroad to account for longer crossing time at a wide crossing. Per AREMA, “If the MTCD exceeds 35 ft, clearance time is one second for each additional 10 ft., or portion thereof, over 35 ft.”
Total Minimum Warning Time (MWT)
: is the sum of the minimum time (MT) and the clearance time (CT).
Advance Preemption Time (APT)
: is the period of time that is the difference between the required maximum highway traffic signal preemption time and the activation of the railroad or light rail transit warning devices. This value is calculated by subtracting the total minimum warning time from the maximum preemption time for queue clearance in Form 2304.