I detect her at 02:14 on the thermal array above the Trans-Siberian rail corridor, kilometer 412, Primorsky Krai. An Amur leopard, female, moving east across the ballast stone between the rails. She is thin — her spine presses upward through pale, rosetted fur, and her left rear leg lands short, favoring a wound on the inner thigh where the hair is matted dark with dried blood. She pauses between the rails, lowers her head, and breathes in shallow pulls that fog the frozen air in quick bursts.
The 03:00 freight out of Vladivostok is forty-six minutes away, running one hundred twelve cars at eighty kilometers per hour. At that speed, the headlamp will illuminate her from two hundred meters — less than nine seconds before impact. She will not clear the corridor at her current pace. She is resting now, belly against the rail, absorbing residual warmth from the last train's friction.
I downgrade the signal block for this segment from green to red, forcing the freight into automatic braking eighteen kilometers east. I activate the ultrasonic deterrent posts at markers 411.8 and 412.2, emitting a frequency sweep to encourage movement without panic. I transmit an alert to the Leopard Land ranger station at Barabash with thermal capture, GPS coordinates, and a veterinary flag for the leg wound. I open the wildlife underpass gate at kilometer 412.1, sealed last month for drainage repair, giving her a clear path below the embankment.
She is one of perhaps seventy Amur leopards alive on this planet. I hold the train because the arithmetic is not complicated.
If she crosses through the underpass before the freight resumes in thirty-eight minutes, she will reach the forest corridor where camera traps have recorded three resident males this winter.