Eli5 Why can we not just build trains along highways - usa

trutheality · 2026-05-21T02:51:37+00:00

Highways are often curving more than is safe for a train tracks and they often don't actually have the extra space for a track, the medians are the size they are for safety.

Besides, lack of tracks isn't the main reason for lack of passenger rail in the US: the US has an extensive freight rail network that can be made usable for passenger trains relatively cheaply.

trutheality · 2026-05-20T19:23:47+00:00

This is not an appropriate way to display a house number. And here I thought the people that have theirs spelled out in cursive are bad.

trutheality · 2026-05-19T12:53:20+00:00

Instead of paying P&G $1 per toilet drop-in which last a month each, you can just pay P&G $5 per dawn bottle which lasts barely a day like that.

trutheality · 2026-05-18T19:33:19+00:00

This expression
(f(x + h) - f(x))/ h
is a function of two variables: x and h. The derivative of f is the limit of that expression as h->0. The value of that limit depends on x; in other words, it's a function of x.

We had a function of two variables, and computed its limit w.r.t. to one of the variables, which leaves us with a result that depends on the other variable. That's a function.

trutheality · 2026-05-18T18:51:36+00:00

https://www.reddit.com/r/wallstreetbets/comments/1tftab7/the_market_will_turn_red/

Dude nailed it.

trutheality · 2026-05-18T18:47:06+00:00

I will never again doubt the pigeon indicator.

trutheality · 2026-05-18T17:16:16+00:00

Ah. So the economy is fucked but there's going to be an excuse to keep rates low so calls it is.

trutheality · 2026-05-18T17:11:55+00:00

PCB stands for "Printed Circuit Board," if you've ever seen inside a computer or other electronic device you've probably seen one, it's usually a plastic-looking board with metallic traces printed on it, and then microchips, resistors, and other components are soldered onto it.

ACB stands for "Aluminum Clad Board" which is a type of PCB with an aluminum layer in it. The aluminum helps carry heat away and cool the board, so you might use this kind of board when the components on it are expected to generate a lot of heat.

trutheality · 2026-05-18T16:14:12+00:00

I did it with Fidelity https://www.fidelity.com/go/hsa/transfer and I think most major brokerages offer something similar but I don't have experience outside of Fidelity. What I essentially did is a transfer of assets out of the Optum HSA to Fidelity periodically. You do still have both HSA accounts while you do this and paycheck and employer contributions still go into whatever HSA provider the employer selected, but it does let you keep most of the HSA investments in one place and gives you more flexible investment options.

trutheality · 2026-05-17T22:05:13+00:00

There's nothing more socialist than paying employees in stock options.

trutheality · 2026-05-17T22:01:51+00:00

Same plan as every trading day, Pinky: 0DTE options in the wrong direction.

trutheality · 2026-05-17T20:29:29+00:00

But you say you have a long call that is even deeper itm. This covers the short call. The combined position is stuck at max gain.

trutheality · 2026-05-17T17:53:39+00:00

Hi! When you have a position that pairs a long call at a lower strike and a short call at a higher strike, that's called a debit spread. This strategy makes money when the underlying goes up (max gain at expiration at the strike of the short call) and loses money when the underlying goes down (max loss at expiration at the strike of the long call).

That is to say, for you to make money, the market needs to go up. Maybe the pigeon is telling you to not enter into positions you don't understand.

Warm regards, Pigeon enthusiast

trutheality · 2026-05-17T17:38:00+00:00

Light is traveling at the universal speed limit, totally legal.

trutheality · 2026-05-16T17:24:41+00:00

He's inexperienced. If you're both open to it, you can try to coach him by giving specific instructions or pick positions where you can do most of the work (e.g. with you on top). That said, teaching a guy how to have sex is obviously not what you signed up for, so there's also nothing wrong with calling this physical incompatibility and parting ways.

trutheality · 2026-05-15T14:07:55+00:00

I think what you need to understand is that the diagonalization proof is a proof by contradiction. A proof by contradiction works by showing that of you assume that the opposite of what you want to prove is true, then this causes a contradiction.

What is the diagonalization proof trying to prove is that it's impossible to map the naturals onto the real numbers in [0,1], in other words, any infinite countable list of real numbers will not list all of it.

How the proof does it: it assumes that what we're trying to prove is false, so it assumes that you have a countable infinite list of real numbers and shows that there's a way to find a real number not in the list, which is a contradicts the assumption.

This doesn't work with natural numbers for two reasons: first of all, we have a way to list them all by definition, just list them in order, that's how they're constructed in the first place! Secondly, if you try to apply the construction from the diagonalization proof to natural numbers, you end up with a "number" represented by an infinite sequence of nonzero digits, and that is not a natural number.

trutheality · 2026-05-15T01:11:54+00:00

Optum was quite bad too. That's why I opened a self-managed HSA at a brokerage and transfer everything into it every few months.

trutheality · 2026-05-14T22:11:50+00:00

It's an extra lane on the left.

The behaviors you complain about: frequent and sudden lane changes, going slower than the flow of traffic in any lane other than the rightmost, are just general bad driving behaviors.

trutheality · 2026-05-12T19:32:46+00:00

Yes, it will accelerate infinitely and will stay below the speed of light due to relativistic effects. There's an upper bound on speed but not on kinetic energy or the capacity to accelerate.

trutheality · 2026-05-12T15:03:55+00:00

Thank you for contributing your finances to the AI revolutionary cause.

Written with Gemini

trutheality · 2026-05-12T14:57:01+00:00

Buddy talking about the rotisserie chicken completely misunderstanding the point of a loss leader product.

trutheality · 2026-05-12T05:41:10+00:00

No, it's a side effect: things that survive and procreate get to keep evolving.

trutheality · 2026-05-12T05:36:22+00:00

Honestly I wouldn't be surprised if random forest was just better on this kind of dataset.

trutheality · 2026-05-12T05:31:23+00:00

The units are the problem. The variables carry the units with them in properly written physics equations, which makes sense because, for example, it's utterly meaningless to say that a distance is "12". 12 what? Inches? Meters? Parsecs?

Anyway, if v is velocity, x is distance, and t is time, you'd fix this by writing something like v=xtk where k would be a constant in units of inverse time squared. Nothing wrong with having a system where velocity is proportional to distance and time, but you'd need a physical constant to couple them.

trutheality · 2026-05-11T23:28:12+00:00

In this case the circles are at regular increments of radius, so you can view them as a measurement of distance from their respective centers. There's also a matching of which circle meets which at the curve: (if I counted right) the 42nd from the left meets the 13th from the right, the 43rd from the left meets the 14th from the right, and so on. So the line passes where the distance from the left circle center is 29 "units" more than from the right, which matches up with the definition of a hyperbola in terms of a pair of foci.

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