Doorways Ad Infinitum

Deep in our former metropolis under orange streetlight and black sky a jaded Private Eye leant for shelter against a brick wall and contemplated his predicament. His client, the odd brown eyed fellow, had set him up to investigate corruption, hanging like dew in an interconnected web of officials, businessmen and politicians.
But over the course of a morning, working day, and evening, something like three quarters of the possible subjects had been mercilessly eliminated in a few fitful pulses of violence carried out by an unknown. Correlating landscapes seemed to morph across the jet sky, and the private eye felt himself on the cusp of something, a great stinking pit maybe, that he must study for the sake of his own income, but not topple into and likely be corroded and destroyed.

Setting out across paving which shined with fresh wet, he began the hunt. Out there somewhere in the dark were answers, payment, and a murderer. A rival. It was 3.02 AM, the wristwatch insisted, so the next lead would right now be setting up to leave town. Best hurry. The railyard, a no-passengers, industrial set-up, was two blocks along and one to the right. With this distance covered, the investigator climbed deftly but breathless over the yard's iron perimeter onto old, cracked concrete through which grass protruded. The odd floodlight spilled illumination across the flat ground and the rails and locomotives which bided their time. One day, he thought, this will all be soil again. But anyway. There's a client needs a job done here. Focus.
The lead was sitting alone at the far end of the yard, waiting silently. The detective fingered the knife he kept in the largest right pocket of his overcoat as he approached. The next departure is in…well, negative ten seconds. This lead, still dormant, was a particularly special one. The odd one out, you could say, which was the choice target tonight for a very good reason. Today most of the leads had been killed, so it made sense to pick the only subject that was not mortal, in such an excessively mortal day. The rest could already be dead by now.
He approached round behind the lead- a train- and hopped on. It started, just seconds later, to sputter and move. And only two minutes behind schedule. Dumb luck, perhaps, or maybe design. The rusted hulk of paint layers black and crimson shuddered now picking up momentum. Evidently it had rained here recently too, and as the Private Eye moved across the guard carriage and to the door little puddles were jolted upward by his shoes' impact and then dropped unobtrusively back to the floor. With some silent persuasion the door slid open. The guards were evidently elsewhere. Keys hung on the wall, and were quickly snatched up. The detective pressed them tightly together to stop any jingling.
Stretched out before him now was the entire train, a repeating line of doors stretching on for miles. Half the suits the brown eyed client had wanted checked out were implicated with this vehicle, or the cargo it was now carrying. In here were answers. But in a case that was quickly escalating into far more than he had bargained for, the detective wondered if on this train he himself was going to get a lot more than what he had bargained for. In other words, 'is the killer on the train too?'

The first door up from the guard cabin led to a damp and dingy storage area lit by a flickering red light. One enormous knee-high metal crate took up the entire left side of the carriage and stretched three quarters of the way to the right wall, leaving a narrow passage down the right hand side which would lead to the next door. Something hummed inside the box, and the air around it had a cool, chemical texture.
This must be the cargo, or part of it. Not, as the 'borrowed' reports and receipts had claimed, suitcases of cash, tommy guns and liquor. With careful feet and furtive checks into the shadowy corners the Private Eye stalked around the box, mathematically checking for a way inside it. A screw maybe, or a chink where some leverage could be applied. The lone drop of perspiration sliding down his cheek was dyed a pale sanguine by the light, which sputtered like a failing stab victim as he pressed his ear to the cold metal, having abandoned his efforts to actually see the cargo.
There was no noise except the humming. Monotonous and inorganic. The detective felt it was fair to assume there was a connection between the humming and the wintery air about the crate. Furthermore, there was a fan in there keeping something cold. But apart from the humming, there was zilch to go on. No marks on the thing, no odours or biscuit trails. This was a very dangerous job; that much seemed pretty clear by now. Borderline frikkin' science fiction. Anyway, the next carriage was waiting, best take a look. But he didn't. He could not.
The detective felt himself passively frozen in his tracks, held there under the red light and shifting darkness. The sheer gravity of the task ahead seemed to slowly pull him down to sit on the floor. Some damp seeped through his coat but he ignored it. After a quick rifle through his pockets he produced a cigarette and lighter. Cupping his hands he lit up. There. His eyes followed the casual swirl of the smoke and he breathed out as it steadily climbed toward the carriage ceiling. About him the train shuddered but he absorbed every jolt with no reaction. Sighing, he faded into a brief numbness.
I'm being dragged in, he thought, and there could be no getting out. The stakes…everything I see tells me they must be high. Folks are getting killed, for what? The mystery box sitting right there? Just what am I doing, just what are my motives here? Cash? There's other ways to bring the bread back home. If I end up like another body murdered…
Back into the pockets and this time he swapped the box of small-league narcotics for a pistol, a clip of bullets, and a tiny pink photo frame adorned with images of flowers and milk bottles. A tiny static face smiled up at him. He held the weapon and ammo in his right hand and the photo in his left as if he was a set of scales weighing them. He himself smiled for a second then hauled himself upright, hiding the photograph away but keeping the gun out.
Steadying himself against the shaking of the train he grasped the handle of the next door, cold and a little rusty, and pushed the door open. The next carriage, now revealed, was almost a clone of the one he had just left. There was the lone metal crate, sitting there under a sputtering bloody light bulb. All the same, with the exception of that barely visible shape there in the corner, holding steady the levelled seven-shot pistol. In the solid gloom all the Private Eye (backed into his own corner with his arms raised) could clearly discern was the glint of a smirking set of teeth and an odd pair of brown eyes.