Building a Better Train to Brooklyn | Hacker News Reader

Building a Better Train to Brooklyn

danshipper.com

25 pointsdshipper12 comments

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Here's the better train to Queens, under construction.

Overview:

https://www.youtube.com/watch?v=cdIq8EqRl_w

2014 update:

https://www.youtube.com/watch?v=foE_mvdXDP8

Miles of new tunnels. A giant cavern under Grand Central Station. New river tunnels. Most of the blasting and digging is done; now the MTA is building the railroad in the tunnels.

That's what it's like to really do that job.

As someone who commutes on the L train daily, I was really disappointed to see that this was actually a metaphor. I want a literal better train to Brooklyn!

Haha! I feel your pain...rush hour on the L is terrible. Sorry if the title got your hopes up :)

There's a source that I can't find that explains why the L in particular so bad. It's basically that most subway lines (e.g. the 2 and 3) have heavy traffic both ways at both rush hours, because they begin and end in residential areas. The L trip profile is lopsided, westbound in the morning and eastbound in the evening, so the marginal gain in capacity of adding another train to it is less than to another line and the MTA is broke enough they have to make those kinds of choices.

I think it's that the tunnel isn't wide enough to have an express. They already run a shitload of trains on the L track, but there's an upper limit to capacity.

Would an express help with the ludicrous crowding at Union Square? A few months ago I was heading to Brooklyn, and I had to catch it from Union Square to the 8th avenue terminal - otherwise, there was no chance of getting on an eastbound train. (The westbound train was full; when we arrived at 8th, maybe five people got off. Everyone else was just trying to take the long route to Brooklyn, because it was the only option.)

Express trains would help with volume. If an express traveling on another track was just hitting Manhattan stops plus Bedford, Morgan, Myrtle-Wyckoff, . . . That would take care of a lot of the volume that gets packed onto the always-local L.

I wonder if that's related to the frequent full-on outages (rather than just the standard sardine-tinning); last Monday evening the L was out completely due to a cracked rail - maybe the added weight of people on the train creates more stress on the structure?

It's also that there are fewer alternatives to the L, if the L is down, you are kind of screwed. Only the Upper East Side is so dependent on a single line, and that is changing.

Plus, the L has exploded in popularity in the last 10-15 years. It was not that popular 30 years ago. Demand has grown much faster than any other line in the system.

> How do I decide which features to include in my product and which ones to leave out? How do I know if one of the new features I’ve come up with is a good idea?

Here's a key difference between software engineering, and well, engineering. Engineers, in 2015, don't come up with an idea and start pounding on sheet metal. The 787 flew in simulation thousands of times before one existed in real life. Every significant feature was measured and justified with a trade-off analysis, backed up with simulations. When they built on, they had a very good idea of what they were going to get.

Typically in (non software) Engineering the problems are pretty well defined usually along the lines of: "Here is an X make it more efficient"

Where X is Engine/structure/Industrial Process etc...

And the defintion or at least the intent behind the meaning of "more efficent" is well understood i.e. Weighs Less, Consumes less Engergy, produces more torque etc.

In the software world there is a much looser definition of what an improvement is which complicates the issue.

"Engineers, in 2015, don't come up with an idea and start pounding on sheet metal"

There is a good quote from Tesla I was taught as an undergraduate Engineer:

“If Edison had a needle to find in a haystack, he would proceed at once with the diligence of the bee to examine straw after straw until he found the object of his search. I was a sorry witness of such doings, knowing that a little theory and calculation would have saved him ninety per cent of his labor.”

Edison went through numerous protypes trying to design the light bulb. I guess that would be the equivalent of the pounding sheet metal approach.

As we were taught Edison was an inventor, Tesla an engineer.

The modern day equivalent of the inventor would be the achitects and industrial designers of the world, they come up with crazy ideas (by pounding the metaphorical sheet metal) and some poor engineer has to make it work. Maybe software needs the same thing a looser coupling between software designers and software engineers.

In materials engineering there is a similar technique to the articles "misfit analysis" used for materials selection. It is not uncommon to have competing constraints. For example to address a problem like designing a beam section optimally you want a beam thats as light as possible, meets the minimum stiffness requirements (usually with an added safety factor) and is still competitvely costed - depending on how the constraints are weighted (cost vs weight vs performance) it could mean the difference between aluminum, steel or carbon fibre for example. The real science lies in expressing the constraints and weighting them against one another correctly.

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