"Yes!" Pause. "I - what - you just found it? Where? How do you know what it's supposed to do?" 

"In the ruins of a laboratory. It doesn't work, it's too damaged, but I found some notes with it and it did work, once. If I could get it working it would revolutionize everything."

Merrin swallows. "What, um, happened. To the laboratory. That sounds - worrying." 

"I'm afraid it's an all-too-common story. Not a long one, though; I can tell you on the way to see the prototype."

Merrin has some SERIOUS CONCERNS about what kind of disastrously bad research safety standards could lead to 'laboratory found in ruins' being a common story! 

She thanks Dagny for the meal, though, and follows her out. 

Dagny leads her down from the skyscraper (such as it is; even the tallest buildings here don't match the heights of Default) and starts to explain. It wasn't a laboratory accident. She found the motor, and the notes, while exploring an abandoned factory, half-consumed by plants. Jed Starnes, who owned the factory when the prototype was built, died, and his heirs started running it on the principle of "from each according to his ability, to each according to his need". Within a few years, all the good men quit and the place went bankrupt. The buildings were abandoned to scavengers both human and animal, who took whatever they could see a use for, but they failed to see the purpose of the motor. So the prototype was stripped of easily removed parts and the pages of the report were scattered, but enough to be a tantalizing hint remained.

Merrin has so many questions! And concerns! Mostly concerns actually! 

"- Wait, so someone else has been in here and they didn't immediately grab the clearly physics-violating machine which would be completely revolutionary if it works? I mean, I'm skeptical too but it's still worth testing it!" 

"Looters looking for things they could sell to other looters, mostly. I'm not surprised none of them recognized it. I only did myself because I read about the concept as a child, in a book describing how it was attempted for years and given up on as impossible."

"...I guess that makes sense. I - would at least read the notes, I think, even if I were just scavenging for parts, it seems important to know what the parts do if you want to sell them. But I'm...starting to be less surprised when things that seem obvious even to me are apparently very non-obvious to most people in your world." 

"I am as unsurprised that you would read the notes as I am that no-one else did." 

Dagny leads Merrin down into an underground train station, then through a door she opens with a key from her inside coat pocket and into a dark unfinished side passage. As the door swings shut she flips a switch on the wall and dim lights flicker on overhead to reveal a table with a glass case containing a strange and clearly damaged contraption and a grey three-ring binder, both incongruously free of dust.

"Are you...supposed to be working in here?" Merrin says uncertainly, peering around. "I - for some reason I assumed you'd be taking me to the abandoned laboratory, but obviously you would've brought it back. Um. I guess my actual question is whether the construction is finished here and it's structurally safe?" 

"The abandoned laboratory is hundreds of miles from here; this is a supply room for the railroad that we haven't been using for anything for years. I assure you it's perfectly safe."

"Oh, okay, if it's your railroad I would expect you to know." 

Merrin goes for the binder first. She generally expects written documentation to be more informative then staring at an actual mechanism, when it comes to trying to understand something she's unfamiliar with. 

Dagny waits with the appearance of patience, which is kind of equivalent to the reality of patience if you think about it.

The report is missing pages and parts of pages, but it's quite clearly describing a coherent physics that is not the one Merrin learned about in school. The differences only crop up in the limit as certain quantities go to zero, but if you [missing page] a room temperature [severe water damage] you can isolate magnetic monopoles, and if you then introduce a [half of page eaten by a rodent] to the circuit you can use this to reduce the entropy of a closed system and produce a current in a wire with net energy output vastly greater than the energy put in.

Merrin reads through all of this with intent concentration, occasionally making quiet surprised exclamations. Dagny is going to have to keep up her efforts to appear patient for a while. 

"...I think it might be possible here," she says finally. Faintly. "There's - here - it's missing the actual experiment description but I can guess what goes there, we did something similar in school once. Except we were proving that you can't do that, with ours laws of physics. Not that the teacher told us that."

Barely-seven-year-old Merrin, a student who up until that point in her life had spent her entire education eager to please her teachers and be helpful to her classmates, thought this was incredibly unfair. Her frustrated indignation is probably a major contribution to why she still remembers the experimental setup, though, so she almost has to be grateful for that.

"You could run that," she adds, "it's not useful in itself but it'd be a lot faster to test than rebuilding this - I think you're going to need some fairly specialized parts and materials. They'd be easy to obtain in dath ilan but not trivial and I think it might be harder here. But I'm sure you can do it. You seem - resourceful." She says this in a tone that indicates it's high praise. 

Dagny is now holding a notebook and pen. "You see it--what do I need to do, what's the experiment?" Whatever it is, she will find the materials and do it and prove to all the headshaking physicists that they were wrong to give up and she will get her self-powering locomotives.

"I think so! I mean, I follow the hypothesis they were trying to test and it sure looks based on these notes like they ran it and got this result and it's not exactly very ambiguous - I suppose not all scientists are honest and it's probably a lot worse here but it'd be a weird kind of dishonesty, I can't see what it would gain them, it's the machine prototype that would be useful and it either works or it doesn't..." 

Merrin requests a page from the notebook and a pen as well, and works in parallel, talking out loud to Dagny and copying over some of the fragmentary diagrams from the notes so she can try to draw in what's missing. There is quite a lot of verbal fumbling and long hesitations and backtracking as she tries to dredge up decades-old memories of a science lesson she didn't especially enjoy and mostly understood but it took a lot of hours at a whiteboard to sort out the math and even more hours of flash card work to scrape a passing grade on the final test for that unit. And there are some standard-in-dath-ilan parts and materials that English seems to not have words for, so she has to do some guesswork and circumlocutions.

She apologizes at least three times for being so below-average at physics and engineering sciences, but within forty-five minutes Dagny has complete instructions and materials required for the experiment. 

Dagny is beaming like it's unexpectedly her birthday. Merrin is outperforming the best physicists Dagny had been able to find just by being willing to look at the evidence and consider that her beliefs could be wrong, her apologies are beyond unnecessary and she will be receiving a second large check tomorrow and news of the experimental results as soon as she has any. 

Merrin actually feels a lot better about getting paid money for an hour of banging her brain on water-damaged notes and half-remembered science classes, than for a lunch spent spitballing wildly about maglev trains. 

"I hope it works! It would be - really valuable. It sounds like energy production is a much bigger constraint here." 

"Very much so. We have coal and oil but they're costly to mine, and it's a constant race between more efficient methods of extraction and the most easily available sources being depleted."

"...You don't even have nuclear fission plants? I guess that's just as expensive if not more when it comes to building the initial infrastructure, but fuel is an easier problem. I...probably could remember a lot of the design stuff, if you have a physicist on staff who could help prompt me?" 

"I have a few, though they're mostly focused on things like making a locomotive that can handle a steeper grade or a bridge that can be built with fewer tons of steel. What's the fuel and do you think I could get it working faster than the self-generator?"

Merrin's brain has finally managed to catch up to her mouth. 

"...Actually I don't know if it's a good idea to start introducing that here because my understanding is that it's much easier to make very big bombs than it is to make a power plant. I don't think it would be faster than the generator, given that there's already a prototype for that and it doesn't seem to need specialized fuel." 

"And even if you trusted me as much as I trust myself I would prefer not to spread any ideas about how someone else might make very big bombs. I'll focus on the generator."

Merrin nods, slowly. "I think that makes sense. By the way, do we have any idea of who actually designed this prototype? I didn't see a name on the notes but I wasn't really looking for one. If there's any way to find that person, I would want to talk to them."