I chose to interpret this prompt (red, green) as relating to signal lights!

BIG thanks to HouseboatIsland for the brilliant idea and the pre-read, and also to CutCat for beta reading and giving suggestions.

1964

Thomas the Tank Engine usually loves a run along his branch line.

This is lucky, as he does it three times a day—and that's when the work is light!

For many years he had run the line alone, and done a good deal more bustling about than the three passenger runs. But these days there were three other engines dedicated to his line—four, if you counted the quarry's new diesel, whom Thomas breezily assumed was making life a good deal easier for Toby than it had been for him, during the years after the Coffee Pots had departed, and he'd had to shunt his trains himself.

But lately he has a secret. He has become not so fond of nighttime runs.

This was decidedly a new development, given that before they had always been something of a treat. He tried to conscientiously hide his new attitude from everyone, to avoid any queries. This was all the easier, as a few years ago he'd gotten a new driver, who didn't know him nearly as well as his predecessor. Old Driver had known Thomas for longer than Thomas could actually remember. There had been no hiding much of anything, from him.

But Thomas knew how to put a brave face on a thing, and New Driver and Fireman didn't suspect that he was nervous. They did notice that it had become tricky to keep him well-fired after dark… but they supposed that Thomas's recent rebuild was somehow responsible for the change. (The "Came To Breakfast, Dinnee? Rebuild," as it was inevitably to be known for the next two decades.)

Annie and Clarabel knew better, though. They murmured to him gently and brightly at Knapford, after they were all coupled up, and as his fireman worked to maintain Thomas's unusually indifferent steam.

"Never mind, love… Daisy shan't be gone long…"

Thomas scoffed bracingly. But he felt hollow in the boiler.

Well, hollower than usual.

"Daisy can dawdle with that fitter of hers as long as she likes! We ran the line just fine for ages before she arrived, remember? Anyway, Annie, I didn't think you were so very anxious for her to return," he put in, with a sly grin. "Carriage shed a bit empty, without your new best mate?"

Annie spluttered, she and Clarabel started their usual litany of complaints about the swervey new railcar, and no more fussing was done until their departure.

This was the "midnight" train, a new service added after Daisy's joining the roster. The station was near dark and deserted as they pulled away, and it only got darker and lonelier still, when they were switched onto the branch line. Annie and Clarabel trundled along dutifully, but Thomas had to take up some of the slack, as they were tired, and slower than usual. They had already run the line two and a half extra times that day. Duck had taken care of those runs, and indeed Thomas had done a little shunting at the big station late that evening, covering for him until Duck arrived from Ffarquhar back to the yard with the coaches. "Like old times, eh?" Henry and James had laughed, watching him at work, and Thomas had reflexively rolled his eyes and scowled.

Though, as a matter of fact, the train engines were a lot more respectful and tolerable now than Thomas remembered from his own tenure. Somehow a few basic manners had been bolted into them along the way. He wasn't sure whether to credit Duck, the change in Fat Controllers, or the no-nonsense presence of the new Caledonian recruits, but there was no mistaking the change in atmosphere. Oh, it was still properly brisk and even vociferous, but in a more civilized way than yesteryear. He'd been surprised to find he rather enjoyed his two hours playing station pilot again.

And he might have preferred to stay there the night, and let Duck continue to enjoy his own little holiday…

Or he could have taken Toby up on his offer, to do the last round trip of the day, until Daisy returned…

But Thomas could not do that to his old friend. Lately, there was a presence on the line, at night. And, whenever he failed to convince himself that he was imagining things, he worried quite a lot for the others.

Not Daisy so much. She was an all right sort really, but not so quick on the uptake, either. Thomas reckoned she could do this run for fifty years herself, and never once notice anything past her own headlamp.

Percy was out lots after dark, and Thomas had resigned himself to the fact that eventually Percy would notice—if there were anything to notice. (Which there wasn't, of course!) But Thomas also supposed Percy to be a great one for imagining all sorts of things, so he reckoned it should be easy to convince Percy that all was well, should he be frightened.

(Percy had never been frightened in the night, but somehow Thomas didn't register this fact. The small, excitable saddletank just seemed the sort to take a fright, and that, to Thomas, was that.)

Toby, though. Toby was an actual, reasonable engine, who could puff and think thoughts at the same time.

If there was something out there, Toby would see. And, not being as thick as a brick, he would be quite rightfully upset.

No. This was Thomas's line. It was part of his job to look after the others. Especially since at least he knew what it might be—

"Don't be daft, don't be daft," he muttered to himself, puffing ahead, so determined to ignore odd flashes of light and sudden owl-screeches that he was sometimes in danger of overrunning his lamplight. New Driver had to check him more frequently than Thomas's professional pride would normally allow.

But Thomas was busy, in his tiny circle of moving visibility, reminding himself that he was simply being a Very Silly Engine. There were no such things as ghosts, these days. Oh, there had been once, probably—even if you discounted Edward's stories, which Edward had admitted to Thomas ages ago, as a secret just between the two of them, that you could… Thomas could remember himself, though, in his earliest years, when the lines were scarcely built up… there were loads more faceless and silent engines about… and the workmen regularly hung up rosemary and left out plates of milk, in order to pacify the invisible things that would creep from the hills at night…

That was so long ago, though! Thomas rolled his eyes at himself. This was the age of the space shuttle, of the Polaroid, of wireless radio programming, of the hydrogen bomb, and even—yes—even of highly-sprung and right-up-to-date diesel railcars.

There certainly were no longer any fey things lurking in the electric-studded night. Not anymore.

And he was being very foolish, to let the rattling of his own coaches keep catching him off his guard.

Busy and brave, Thomas got on well enough… until they approached the tunnel.

He had been looking forward to the comforting glow of the signal. Electric lights were better at banishing any ideas of haunts than those old salt circles had ever been!

But the signal light shone red.

Thomas's boiler went cold again. "How silly!" he called, trying to resist as New Driver shut off steam. "C'mon—it must be broken! There's no one out but us!"

"Rubbish, Thomas!" scoffed the driver… quite rightly, the engine knew. Danger signals were for more than another train or engine trying up a section.

But oh, how desperately Thomas did not want to stop!

He did screech to a slow halt, though. He couldn't fight the combined efforts of his crew, as well as his own ingrained sense and long habit. It was immensely idiotic, to ignore a signal. You weren't in service for going on fifty years without developing Pavlovian reactions to them.

Immediately Annie and Clarabel could hear, first confused questions, then rising complaints, from their passengers. As they heard them, Thomas knew it was happening. They didn't need to tell him as much: They were so closely bonded that, whatever they heard from their interiors, the knowledge percolated along the very heat-pipes into his own smokebox.

Right now all three were agitated, for they hated to displease their passengers. But there was an extra layer of tension, as they waited, sitting targets in the dark.

"Never mind!" Thomas hissed back to them. "Better safe than sorry… better safe tha…"

There was a whistle in the distance.

But he'd been thinking he'd heard that whistle now and again all season long… and he'd always been wrong before.

"… th-than sor—what IS that signalman playing at?"

It was a single track line. If the other train was going to be diverted, it should already have been so. There was one of the Ffarquhar line's rare wait sidings up ahead, but it sounded to engine and coaches as though the shrill, endless whistle must have already passed it.

The other engine kept rattling along, its pace quite brisk, its train loose and clanking. There was no hint of it slowing.

Thomas's lamplights started to flicker badly, in his fright.

Then there was a pinprick of light visible through the cavernous-looking tunnel.

"Get out!" Thomas whistle-shrieked in horror—to his crew, to his passengers, to all the humans on his train, who could move—

"Thomas, is someone com—?"

Clarabel never finished her question, and Thomas never heard it anyway. He was now face-to-face with a pale, wispy, see-through figure. An engine made of smoke. Her boiler raised vertical and tall, her buffers enormous, everything about her familiar... including her expression of knit-browed determination…

She was not, apparently, determined to stop.

With a roar of fire and screech of unoiled axles, she barreled right into Thomas—right through Thomas, and through his whole train!

Thomas, Annie, and Clarabel screamed.

As the sound of the strange rushing train faded, the silence became profound, save for the hooting of owls and the shivering of their own axles.

"Annie! Clarabel! Are you all right?!"

"Y-Yes, dear—"

"NO!"

Thomas was too numb and shocked to react, but Annie's emphatic denial was , on some level, strangely bracing.

"We—We just—Good Lord!" Annie wailed. "We were just run through by a—by a—"

"Ghost train," Thomas chorused with her, his own voice uncharacteristically hushed and soft.

"Oh, Thomas darling," shuddered Annie. "Are you all right?"

"Oh, have—have we our signal now?" Clarabel was shamelessly eager to get started again.

"Do you have a fire, to move?" chimed in Annie, more practical.

"I—I—was— was that…"

Thomas swallowed. The name was painful to say. In truth, he had not said it for many years now—not said any of their names.

"… it was J-Janey, wasn't it?" he whispered.

Clarabel had been able to see the train depart round the bend. "Y-Ye—oh, Thomas, I don't know—that wasn't Janey—but—b-but yes, it looked like her to me, too. And the flatbeds she was carrying…"

Thomas had not seen that at all. Mostly, he had been too busy screaming with terror and with real pain as the train had run through him. It had been so cold …

Engines hate the normal cold. But that icy wet air had been like nothing else …

"W-What was she carrying?"

Thomas couldn't make himself heard over the crickets and the whoosh of damp air through the leaves. But Clarabel continued anyway.

"… she was… she was… oh, you two didn't see it? I oughtn't—"

"Clarabel!" scolded Annie, a note of hysteria in her tone.

Clarabel didn't need more than that. It was the knowledge that drives one mad, if kept to oneself. "… the boys were on the flatbeds… Glynn, and Afon, and Reese… in—in—"

Thomas knew what it must be. "In scrap condition?"

He put the question with a hollow gentleness, and it broke Clarabel's professional composure. "Oh!" she said, with a sudden sob. "O-O-h-h-h, I'm—yes, darling, I'm afra-a-aid so—!"

The engine at the head of the ghastly train had spoken not a word. But all the sounds of her running were true to life, so loud, so real, so indistinguishable from a real train! And now, Thomas couldn't help but hear Janey's voice, starting to form in his smokebox. He was terrified to know what she had to say—

And yet—

There was something so compelling, too. He wanted—he needed —to hear her voice… one more time.

"Thomas! THOMAS!"

It was not Janey's voice. It was New Driver's.

He was a gentle man—notably less strict than Old Driver—but his tone was exasperated. Somehow, Thomas became aware that he had been shouting to get Thomas's attention for some time now.

Still bitter cold, but with the night a little less quiet, the tank engine's eyes flicked upwards by instinct.

The signal light shone green.

"Come on, lad!" The fireman rapped the side of his cab sharply. "What are you playing at, then?"

"Th—Th—Th—"

("Jesus," said New Driver, to the fireman. Thomas winced, raw. There was no anger there, but there was something so painfully mundane in the driver's voice. "Something's got 'im good and spooked…")

Spooked!

Like some fresh baby loco!

"Th-Th-The signal—when did the signal turn green?!" demanded Thomas, finding his indignation again… if not his fire.

"Is that why you stopped?" New Driver now sounded completely baffled. "We're all clear! What happened to your boiler pressure, now?"

It took twenty minutes to raise it again and to get off the brakes.

Twenty minutes in the dark, in the the cold, in the absolute horror. The whoosh of wind waving the trees made Thomas and the coaches feel they were sunk at the bottom of a nightmare ocean. Light, sound, and sanity were all too distant for comfort.

Thomas tried, through chattering teeth, to explain to his crew that it wasn't only him who was "seeing things."

But humans can't hear the speech of coaches and trucks, so citing Annie and Clarabel's witness did not get Thomas very far in convincing his crew that the signal had been red.

Given that failure, despite his sheer misery... he kept the rest of it to himself.