Thomas arrived at the construction sight a few hours later, having been delayed by slow running trains. He grumbled as he pulled in. "It's not fair, it's not fair..." he grumbled. "I get everything taken away from me all over something that wasn't my fault! Can this day get any worse?"
"Yes, statistically speaking," Twilight replied. "There could, for instance, be a boulder rolling down the line before us. Or a diesel with a big claw could chase us down a mainline."
"I somehow don't think that's likely," Thomas said, then glanced over to see who was at the rest point. "I believe we've met before," he said to the red diesel.
Salty smiled as he glanced over. "Ahoy, me hearty!" he said. "It be the blue tank engine of legend!"
"Thank you!" Thomas said. "It's nice to find somebody who knows who to talk to engines."
"As a fellow engine, I logically would know," Salty smiled. "Sunny? And old friend is here!"
"Just a second!" a familiar voice replied. Thomas had gotten used to hearing that voice many times during his days in November when Twilight had gone missing. "Need to check calibration of the vacuum brakes!"
A few moments later, Sunny's face popped around the side of the other locomotive, followed by the rest of her body (as a floating head would be a rather bizarre sight to say the least). Her face was already cheerful, but broke out into an enormous grin when she saw Thomas. "Hey Thomas!" she said. "It's been a while, hasn't it?"
"Sure has," Thomas said. "Say, how have things been on the mainland?"
"Pretty good, if somewhat chaotic," Sunny replied, as she sat on Salty's running board. "All sorts of ghosts, repeated encounters with crazy things-"
"Discord?" Thomas asked.
"Thankfully not," Salty said. "Or else we'd be all out to dry with no wind in our sails!"
"Well, when you put it like that," Thomas said, "we've had an easy few months here in comparison. But something very odd happened today."
"I don't think Sunny needs to know about that, Thomas," Twilight said.
"She might be able to cast some light on the odd signal thing we encountered," Thomas said.
"Odd signal thing?" Salty asked. "Now you've got this old sea dog's attention."
"Yeah, that does sound serious," Sunny said. "May I get some context on that situation?"
So Thomas explained to her what had happened at Knapford earlier that day. Safe to say Sunny was a bit surprised. "I've never encountered a fault like that," she admitted. "But then again me and Salty usually work in a yard with no signalling, so we don't have to worry about that."
"It sounded familiar to me, though," Salty said. "Once, a long time ago, there some incorrectly wired signals on the main line, and a disconnected relay was activated by a false electrical signal. Once that happened, a signal went from red green when it shouldn't have done. A train was behind the signal, and it moved off- and crashed into the train in the block in front."
"I hope nobody was hurt," Twilight said.
"Sadly, there were several deaths and many injuries," Salty reported. "All of that caused by some shoddy maintenance work."
Just then, Isaac arrived. "Was there something you needed me to look at?" he asked. "Or is the issue resolved?"
"Nope, it's all good to go," Sunny said. "This is Isaac Moonbow, Izzy's dad."
"I don't believe we interacted," Thomas said. "Nice to meet you, Mr Moonbow."
"Likewise," Isaac replied. "Now, what was that about faulty terminals?"
"Thomas was involved in an accident involving signals at Knapford," Sunny said.
"And it was faulty signals at that!" Thomas said. "The signal changed as I approached it, which shouldn't happen!"
Isaac nodded. "I deal with computer systems on a daily basis as part of my job maintaining and running oil rigs. If the signal system is computer controlled, I might be able to investigate the fault and find out what's going on."
"Please do!" Twilight said. "If nothing else knowing what happened would help greatly with my anxiety."
"Consider it as good as done," Isaac said, and soon he was on his way.
"Thank you so much," Thomas said. "You know, it was strange how quickly he had another engine lined up to replace me. Almost as if this was planned somehow."
Just then, Rebecca steamed in with some fresh hoppers loaded with ballast. "I don't know if I'm coming or going and it's only noon!" she said, with a tired smile. "But it's an interesting return to the past- I used to work ballast trains out of Meldon Quarry back in the day, and those were quite heavy."
"That's where we get most of our ballast from, isn't it?" Salty asked.
"It is," Sunny replied.
There was another sound as Charles returned from the build site- with more loaded hoppers. "Just what we needed," he grumbled.
"What happened Charles?" Rebecca asked.
"There's ground subsidence at the build site," Charles complained. "The ground was shifting as I approached. The construction crews told me to pull back to a safe distance whilst they installed some barriers and safety equipment. They'll carry what they need to the build site and avoid using engines, so they putting up a stop board to tell us where to stop."
"That's quite useful," Twilight said. "Provided the engine in question obeys the stop board. Right, Thomas?"
"You just had to mention that, didn't you?"
The sun continued to move through the sky as the engines continued their day, relatively merry. Thomas was feeling something of a sense of peace here. Far away from Sir Topham Hatt and his wild accusations, Thomas was in the company of friends and engines who saw him as an equal, not an engine to blame when everything went wrong.
Having said that, he was certain Sir Topham Hatt would come to his senses. I mean, he always had in the past. Why would this time be any different?
Isaac looked closely at the display terminal at Knapford south box, which controlled the signalling systems on that side of the station. The display contained all the readings and data he would need to diagnose the problem with the terminal, and so he got to work, typing in the codes he needed to access the data required to crack this puzzle open.
"Right then, let's see what I can find within this system," he said, mainly to himself as he continued to move and process data about to find what he needed to solve the mystery.
At last, he found it, and his eyes widened in surprise at what he saw. "If that had happened on one of the rigs it'd make Piper Alpha look like a firecracker." He quickly ran a program to compile the data, and then indicated to a printer to print out an automatically generated report. Once this was done printing, he exited the lower levels of the signal box.
"Did you find anything, sir?" asked the signalman.
"Yes, and it's not good," Isaac replied. "I'd advise shutting down the box whilst it is investigated."
The signalman nodded. "Understood. Locking out the box and transferring command to Knapford North box. You know sir, it was strange. I thought the interlocking was behaving abnormally this morning. I tried to mention it to Sir Topham Hatt but he brushed me off for some reason."
"How very odd," Isaac said. "I should have more luck- I doubt he'd disregard the words of a trained systems engineer."
Isaac then made his way to the station, and after walking onto the platform stood outside Sir Topham Hatt's office. He then knocked.
"ENTER!"
Isaac entered to see the head of the railway on the phone to somebody. "What do you mean you can't get through? Get some power tools and chop it into bits!"
He placed the phone down, and looked over. "Ah, Mr Moonbow," he said. "Tell me, what did you find?"
Isaac placed the report on his desk. "The signal failed. A malfunction in one of the terminals caused the interlocking to disconnect and a rogue wire resulted in the signal displaying a false green aspect. You need to get the terminal replaxed and the wire resoldered. You should consider yourself very lucky that the accident wasn't more serious- if a loaded train had derailed at speed on those points you could have been looking at a repeat of the Potters Bar crash."
Sir Topham Hatt nodded. "I'll send it to the Office of Rail and Road right away." He smiled. "Enjoy your time on Sodor, Mr Moonbow. Anna enjoyed it here last November."
"Who's Anna?" Isaac asked.
"Your daughter, as in Annabelle, right?"
Isaac shook his head. "She's called Izzy, short for Isabelle." As he left the office, he shook his head. "Weird he should get that one wrong. Izzy's spent far more time here than me."
Sir Topham Hatt closed the door, and looked at the report. "Let's get rid of this," he said, and he dropped it in the shredder.
Back at the worksite, the engines were working with the new parameters. Thomas had been put to work taking explosives to the construction site, as far as the stop board of course. Twilight coupled him to the train, and all seemed to be well at first.
They puffed down the line with the wind whistling along past them at speed. It all seemed like very easy work indeed for them, until of course it stopped being easy.
Twilight looked about. "They said their should be a stop board along the line where the workmen will be waiting," she said. "Eyes on the lookout, Thomas!"
"On it!" Thomas said, although his view was obstructed by his trucks sitting in front of him. He continued to rattle on his way, seeing the scenery roll by. "You know, I hadn't considered how pretty this bit of the island is."
"Eyes on the rails, never mind the view."
"I've heard the story of Duke from Pear, you know."
Just then, as they rolled along, Twilight suddenly felt the ground seem to shift under them. "Wait, where's the stop board?" she asked, confused.
"I can't see one either!" Thomas said. Suddenly, they lurched to one side, and the trucks in front of them tipped over, discarding their cargo onto the ground, which was still shifting. The coupling had broken, but in that moment the explosives onboard detonated, blowing a vast hole in the floor.
Thomas was left hanging precariously over the gap, looking down into a vast cavern. "Cinders and ashes! I'm stuck! HELP!"
A few minutes later, Porter pulled Thomas back. "Thought you'd have had enough of falling down mines, mate," Porter joked.
"Not funny," Thomas said. "I could have fallen in!"
"Well, the stop board was there for a reason," Izzy pointed out. "Trains have to stop at it."
"That's what's weird, though," Twilight said. "There was no stop board at all! If the ground hadn't collapsed we'd have had no clue where to stop!"
"That is strange," Izzy conceded. "There was one a few minutes ago. But why would they remove it?"
Thomas was about to reply, but then saw a strange glow coming from the hole in the ground. "Did you see that?" he asked.
"See what?" Twilight asked.
"Something was glowing under the ground," Thomas said. "Have we found a secret cavern?"
"Perhaps best we let the official investigation handle this," said Twilight, who looked behind her. "We haven't exactly made a good first impression, have we?"
"Seems that way," Thomas sighed. Any moment now he knew the infamous musical cue would play and there would be something about confusion and delay.
At last they came to a stop in the yard, where everybody showed the appropriate level of concern.
But what had been in that cavern? That was all that was on Thomas' mind right now. How could they find out what had been down there?