Pinta, North Siding

A flood of hot eastward trains descending upon Pinta has forced the dispatcher to order extra east BNSF 4850 to take siding, and as not to delay the Z trains any further, the conductor was asked to line behind and walk the train (often the conductor will hitch a ride on the headend). Dwarf signals on all D-251 sidings are absolute signals (lacking number plates) and prevent a train from entering the main if any train is, in most cases, three blocks behind. For Pinta siding, the eastward dwarf drops red once an eastward movement passes signal 2252. In the background is mainline signal 2182, installed field-side when the CTC island at Coronado Junction was constructed in the mid-80s to handle coal trains to the St Johns power plant. Once the mainline movement has passed 2182, and provided there is no following mainline movement between Pinta and signal 2252, the dwarf signal will go yellow, its least restrictive aspect (there is no flashing yellow or green). But even if the signal is not restrictive, the train needs permission to leave the siding by the dispatcher. In the days before radio, when trains where dispatched by timetable and trainorder, a freight train was only required to clear first class trains or that instructed by a trainorder. So it was generally the case when the last first-class movement had cleared, and the dwarf flipped to yellow, the headend would immediately foul the circuit, preventing any following movement to "stab" the train in the hole. Stories abound how one freight would try to leap frog another by following close on the heals of a "slow" first class movement, preventing a head-out dwarf from clearing.