The scenery outside the windows slows, then stops. Calypso stumbles, catches herself against a brass handrail. The connecting doors hiss shut between the cars with a pneumaticfinality.

A voice echoes through hidden speakers in a smooth baritone. "My apologies, passengers. We seem to have encountered an unscheduled stop. Please remain calm in your current locations until we are underway once more."

The lights flicker, dim. An unfamiliar grinding sounds begins somewhere beneath the carriage, rhythmic as a heartbeat. The floor vibrates with it, a sensation felt in the bones.

The wheels have stopped, but the train itself feels almost alive around her, breathing through vents and pistons in the dark. Waiting. The rhythm continues, steady, inescapable. Building to something.

O...k. She's going to go see what's up with the engine. She slides open the door to the next carriage.

The connecting door hisses open, then sticks halfway. She has to put her shoulder into it to wedge through the narrow gap.
This carriage is dark, empty. The seats are shrouded in gray dust covers. The windows are black, as if night has already fallen outside. The pneumatic tubes for calling the conductor hang dead and silent.
At the far end, the door to the engine compartment is shut fast. No light shows beneath it. As she makes her way down the aisle, the vibration through the floor grows stronger, traveling up through the soles of her shoes. The grinding sounds like the turning of enormous gears,
huge clockwork components meshing and winding.
She rattles the handle of the engine door, finds it locked. Pounds on it, calls out, "Hey! Anyone in there?" Her voice echoes in the dead space, swallowed by the noises from below.
A hiss of steam, an acrid smell like burning oil. The carriage shudders around her as the heartbeat rhythm doubles its pace.

Is the engineer in the cabin? Or the fireman?

No response comes from within. The engine compartment remains dark, sealed. If anyone is inside, they do not acknowledge her shouts or the pounding of her fists on the metal door.
The train itself seems to have taken on a life of its own. The components far beneath the carriages grind and churn with an urgency that suggests intention, purpose. The vibrations have spread up through the walls and floor and into her bones, as if the train is now her own heartbeat, her breath, and she is a part of its workings.
The smells of hot metal and burning oil grow thicker. Wisps of black smoke begin to curl up from between the floorboards, only to be snatched away again by some unknown vent or aperture.
This is not a straightforward mechanical failure. The train is driving itself now, fired by some essential momentum, advancing toward a destination known only to itself. And she is trapped inside its burning, restless heart.

This is not normal train behavior. They're odd things, but not usually this odd. Did the carriage look like this last time she was in here? She's going to look out a window.

Calypso makes her way to the nearest window, rubbing at the thick layer of grime and soot obscuring the glass. What she sees outside makes no sense.
There is no countryside, no city streets, nothing familiar. Only a sea of deepest black, empty and still, stretching endlessly in all directions. Not night - for the blackness seems almost substantial, as if it might pour in through any opening and drown the carriage in darkness.
Panic rises in her chest. This cannot be. However strange its behavior, a train must travel between two points, along tracks that pass through real places. There are no tracks here she can see, no destination that could possibly lie within this void.
The train has left the world behind. It drives itself now through landscapes not meant for human eyes, stoking its furnaces with a purpose of its own. And she is alone here, sealed within its fire and mechanisms, helpless as it carries her further into shadows unknown and unmapped.

No panicking. That's not sensible. She needs a plan.

1. Is this her train at all? If not, she needs to get back to her train at once.
2. If it is… well, she is the conductor. She needs to find and protect her passengers.

Calypso takes a deep breath, steadying herself. Panic will accomplish nothing.
There seems little chance this nightmare carriage is part of any normal train she has conducted. Which means her true train, her passengers, may still remain where she left them, waiting for her return. She must find a way out of this place, these impossible shadows, and back to the familiar world she knows.
The door back to the previous carriage is still jammed halfway open. That seems her only exit now, if she can force it the rest of the way. She braces herself, shoves hard against the unyielding metal, throws her full weight against it until at last, slowly, it scrapes open another few inches.
Black smoke pours through the gap, carrying the stench of burning with it. The floor trembles violently under her feet as the grindings from below rise to a roar.
This train, whatever it may be, has no intention of releasing its captive so easily. But she is the conductor, duty-bound to protect those in her care, and she will fight her way free of its depths if she must, or die trying. She squeezes herself through the smoldering narrow opening, drops onto the floor of the next carriage, and runs toward the unknown finale of its journey into darkness.

That's a bit dramatic, don't you think? She's going to walk, checking all the windows and compartments carefully.

You're right, running headlong into potential danger would be foolish. Calypso proceeds cautiously, walking the length of the carriage while checking each window and door along her path.
The view from every window remains the same impenetrable black void. The doors to compartments and facilities on either side are all sealed fast, locked or jammed. The only open exit remains ahead, through the connecting door at the far end leading further into the train.
The vibrations and sounds around her intensify, as if the massive gears and pistons driving this nightmare are working harder now against some unseen resistance. The smoke trailing behind swirls thicker, oily tendrils rising to grasp at her as she passes.
Each step brings her closer to the unknown. But turning back is not an option - there is nothing behind her now but darkness. Her only hope remains in pressing forward, finding her way through this impossible maze, and out the other side.
At last she reaches the end of the carriage. The connecting door there has been wrenched off its hinges, opening into a narrow, dimly-lit passage beyond. The floor trembles; the grinding echos louder from somewhere close ahead. Clouds of foul-smelling smoke pour through the doorway to envelop her.
The heart of the thing must lie just ahead. And there may be no way out but through it.

Hmm. Can she open a window?

Calypso moves to the nearest window, examining the edges closely. The glass itself seems ordinary, but the mechanism for opening it is missing - no handles or levers to grasp. She runs her fingers along the narrow gap between window and sill, hunting for any switch or catch that might release it, but finds nothing.
The window remains as firmly sealed as all the others. Whatever malevolent force has brought this train into being evidently means for its captive to remain inside, with no glimpse of anything beyond the shadows that surround it.
Still, where there are no obvious locks or fastenings, there may yet be a way to pry it open through force. She searches the carriage and finds an abandoned hat stand, now cobwebbed and rusted, but with a sturdy metal base.
Bracing herself, she swings the base hard at the center of the glass pane. A shudder runs through the floor beneath her feet, accompanied by a bone-jarring metallic shriek, as if in protest. But the glass merely trembles under the blow, not even cracking. She strikes it again, and again, with all her strength, but cannot leave so much as a chip in its smooth, dark surface.
The train's masters will permit no escape, through doors or windows or any other portal. Its sealed carriages contain untold dangers, but also the only path remaining forward - into the fire and churning gears that even now call out for sacrifice to feed their ceaseless purpose.

Honestly, she wishes that the windows were this resilient to unruly passengers. Anything in this room that might help her be more prepared for the next chamber?

Calypso searches the carriage thoroughly for anything that might serve as a useful tool or weapon. But there is little here left intact.
The few furnishings remaining are broken, cobwebbed relics - useless for defense or leverage. The electric lamps hang dark and cold. Each door or hatch she tests proves jammed or locked beyond her ability to budge.
Amid the detritus, she spots a glint of metal - the spokes of an old wheelchair, abandoned and rusting in a corner. She wrenches at the spokes until two come loose, corrosion crumbling as they twist free. Rough, narrow clubs, but solid enough to strike a blow.
There is a sharp crack as she levers up a slat from one of the bench seats. Rough wood, jagged at one end, as long as her forearm. Not ideal, but better than nothing.
A final prize comes in a battered first aid kit still bolted to one wall. She breaks it open to find gauze, salves turned to dried lumps, a rusted scalpel...and a half-full bottle of chloroform, stoppered against the ages.
These broken, makeshift tools offer scant reassurance. But they are relics of the real world, a world now lost behind her, their solidity strangely comforting in her hands. She has found all this place intends to provide by way of arming its hostage against the dangers ahead.
Thus equipped - and steadied by a breath to quell her nerves - she turns toward the open doorway gaping at the end of the carriage, a portal into the churning, smoking unknown, and the heart of the nightmare.

A strange soldiery she makes. She grips the spoke in her hand, and pulls open the intercarriage space, stepping through and slipping to the side, hoping to get a glimpse of something nonvoid.

Calypso takes a firm grip on the metal spoke, holding it ready as she eases through the open doorway into the space beyond.
The intercarriage passage is narrow, dimly lit by a flickering glow that emanates from somewhere further ahead. The walls tremble around her, metallic groans and grindings echoing through the confined space. Acrid smoke swirls thick enough to burn her eyes and catch in her throat with each breath.
She presses herself against the trembling wall of the passage, inching forward step by cautious step. The floor shudders under her feet as if some enormous, overtaxed engine strains below, building its fires ever higher.
At last she reaches the end of the short passage. The doorway opening into the next carriage has been torn away, giving onto a scene that makes no sense.
There are no seats here, no tables or furnishings of any kind. This space has been gutted to make room for gigantic gears and churning metal components, pistons driving with furious urgency, spilling smoke and sparks with every stroke. The floor has been grated open to reveal a massive furnace below, fire raging hot enough to scorch the air and set her choking.
This is no train carriage. This is the molten heart of a machine rage incarnate.
She has gained her first glimpse of the forces that now hold her captive. And they brook no escape from those trapped within their burning, grinding depths.

Calypso coughs, and squints through the smoke. This is quite impossible. But there, just visible through the machinery, is a familiar outline - the door to the next carriage. Her passengers must be there.

She picks her way around the churning gears as quickly as she's able, sliding over grated floor panels to avoid the roaring furnace beneath. The metal slivers tear at her clothes and cut her hands, but she finally reaches the door, breathing hard. It slides open at her approach.

Calypso scrambles across the churning gears and hissing furnace grates, beelining for the door at the far end of the carriage. It slides open at her touch.

The space beyond is hazy with smoke, but familiar - rows of dusty seats, luggage racks. The windows show blackness, yet faint sunlight gleans through. The end of the carriage is torn away, revealing green hills and blue sky.

She tumbles out onto soft grass, gulping clean air. The impossible contradiction of a train without tracks remains behind, sealed and dark. Her passengers stay trapped within.

But she is free. She weeps in the sunlight, grieving even in her joy. The shadows have released their captive, if only for now. The world is real once more.

Calypso stumbles to her feet, wiping her eyes. No time for tears. Her passengers are still trapped in that infernal contraption, and she must find a way to free them. She circles the impossibility of a train sitting in open grassland. The doors and windows are sealed tight, unmarked by the damage inside. She pounds on each one, calling out reassurances to the muffled voices within. There's only one way back in - through the furnace and gears. But now, in daylight, their metal is cold and still. She picks her way back through ruins that seem decayed with time, emerging soot-stained into familiar carriage walls. Her passengers cluster around her, tearful and dazed. "All's well!" she calls with a confidence she doesn't feel. "There's been some trouble with the...engines, but we've arrived safe and sound. Now, if you'll just follow me..." The way out seems straightforward now, a quick walk from nightmare into waking. But as she leads them through grass and sun, a doubt niggles at the back of her mind. Did any of that seem too easy?