The engineer of the Southern Pacific westbound express train squinted into the black night air as the locomotive emerged from a cut in the rocky terrain and spotted a red light in the distance, swaying in the middle of the tracks.
Colonel Harper, the engineer, reacted quickly and applied the air brakes, reversing the engine.
Sparks exploded from the big iron wheels as it skidded along the rails, slowing to a stop about an engine length from a barricade of railroad ties piled across the track at Papago Station, about seventeen miles from Tucson.
Hanging from the piling was the red lantern Harper had noticed earlier.
As he glanced at his watch – 9:55, April 27, 1887 – a volley of bullets thudded into the mail and express units behind the cab from the hillside bordering the train.
Two masked men sprang out of the darkness with guns drawn, climbed into the cab, and ordered Harper and John Clancy, the fireman, out.
Once the Southern Pacific men left the cab, a couple more masked outlaws joined them.
After taking $12 in cash from Harper, they forced sticks of dynamite into his hand, and that of the fireman.
“Take this dynamite and go down to the mail and express cars,” one of the men told him.
“Tell your agents to open the cars and surrender, or you will blow up the cars with dynamite.”
Harper, who was threatened with death if he failed, called out to the Wells Fargo express messenger and the mail agent who abandoned the cars.
A couple of the bandits uncoupled the mail and express coaches from the rest of the train, while the others cleared the track of the barricade.
All of them got aboard the engine. A couple of minutes later, however, one of them leaped to the ground and escorted Harper back to the cab.
“I was then made to show them how to work the levers, and told to start it easy, and after it was going jump off, which I did,” Harper said.
Five miles up the track, the gang cleaned out to express and mail units, disabled the engine, and then left.
Well Fargo put the loss from the robbery at between $3,000 and $4,000.
The quick-thinking express agent, CF Smith, managed to hide $5,000 in a stove before opening the door to the robbers.
No estimate of loss was available for the stolen US mail.
According to Harper, there were five men, all masked. A six man stood on the banks with his head lowered and dispatched orders to the others.
When word of the robbery reached Tucson, authorities organized a posse and alerted military authorities, as well.
Southern Pacific and Wells Fargo both offered a $1,000 reward for the arrest and conviction of each robber.
The unknown outlaws, who were pursued but never found, committed what is believed the first train robbery in Arizona history.