If Train A is traveling East at 35 MPH and Train B is traveling West at 45 MPH ...

I use a lot of basic math, like addition or subtraction, but never do I algebra which I took in 12th grade. I measure very carefully, maybe twice and then cut to fit if I have to. I go with the recommendations for wiring taken from the NEC code book for wire sizes.

Even when doing track placement it can be placing it to fit. Adjusting the track clearance when seeing if 2 engines or 2 passenger cars can go through parallel curve tracks. 

Lee Fritz

I use math all of the time at work. I make store window displays.

Some of the things that come up for me daily are very similar to what we do in this hobby?  How much can I get out of a sheet of plywood? Cut maps, cut lists. The geometry of angles and how to make sure things fit together seamlessly.  How much do I order with a small safety margin without blowing the budget or creating a storage problem? If I am hanging something from the ceiling how much weight can I hang safely using the least and thinnest lines. How quickly can I do something. How quickly can others do something (this is always amazingly different)? When I need things how can I order to get them in time and so we don't run out. Fun stuff that I deal with daily. 

try this scale converter Anything smaller than 1/4" (.25) is too small to worry about. A 1/4" 1:1 is really too small in 1:48.  6" 1:48 scale is slightly larger than an 1/8" 1:1.

Do you work at a lower accuracy? 1/16" 1:1 is close to 3" 1:48  That's about as small as I would want to work.

It's pretty straightforward.  Divide the 1:1 dimension (in inches) by 48, yielding the equivalent O scale dimension.  For 1:1 dimensions in feet, divide by 4.

1" (prototype) / 48 = .0208"

12" / 48 = .25"

1' / 4 = .25"

The opposite also applies to convert a dimension scaled off of a model into 1:1 sizes.

I use this functionality all the time to convert prototype dimensions to scale sizes so that I can seek out appropriately sized styrene sheets and shapes.  I can also use it to scale dimensions off an HO model and convert them to O scale.

(HO x 87) / 48 = O....or more simply HO x (87 / 48) = O

Moonman posted:

try this scale converter Anything smaller than 1/4" (.25) is too small to worry about. A 1/4" 1:1 is really too small in 1:48.  6" 1:48 scale is slightly larger than an 1/8" 1:1.

Do you work at a lower accuracy? 1/16" 1:1 is close to 3" 1:48  That's about as small as I would want to work.

6" at 1:48 is actually exactly 1/8" at 1:1.  And 3" at 1:48 is exactly 1/16" at 1:1.  The converter is rounding up to only two decimal places.

One of the nice things about O scale is that it converts conveniently into scale dimensions that we are all pretty comfortable with already....unless one prefers metric!  It also helps somewhat that 1/4" = 1'-0" is a very common drafting scale, so things like building plans and sizes can be very easy to relate to.

Now does the line have some sort of PTC which is on line?  ATS?  Passing siding?  If they meet, it would more than likely be at speed, so onew would have a "Corn Field" meet.  And there was no location for each train at the start of the verbal proplem?

Phillyreading/Lee: I know what you mean about those clearances. I'll never forget feeling so clever to see my two engines and their consists running side-by-side for the first time until they rounded a corner and some cars lightly grazed one another.  Serves me right for not doing a manual dry-run first.

Silver Lake: You have presented an amazing list of uses for math in your job!  It goes well beyond the obvious to include things like weight for hanging and time management, but it is so true.  Although I am a "technical" writer and work with physics PhDs, I never use math for my job (stuff like COBOL, maybe, and a hint of logic/decision flow here or there ... but no math :-).

Rattler21/John: Unfortunately, my elementary school stopped using slide rules when I got to whatever grade it was that normally introduced them. So my brother got one the year prior and as a result I always though they were mysterious and cool and only used for square roots.  I'll see if there's still one in the family somewhere.  It would be fun to finally master it.

Moonman: Your link to an online converter is exactly the sort of tool that I was looking for.  Thanks! It will come in very handy and save me from writing a program.  And how great that it includes conversions to other scales.  Since my layout is carpet-based and must be moved and my budget modest, I have looser standards for accuracy than I might otherwise like but I get your point about how some precision is meaningless at certain sizes.  What has always interested me, 'though, and which is somewhat related are the decisions that model makers make to step outside of a literal interpretation of the scale.  It reminds me of being a charicaturist some years ago. I had to make an active decision as to what facial features to accentuate and what spaces to show or play around to create an impression that is identifiable as a person.  It's the same thing with a drawing that will be mechanically reduced without loss of recognition -- say for publication. You need to accentuate somethings and downplay others to have the end result be recognizable at a given percentage.  You can see this in Matchbox cars in particular.  Somethings are a little out of scale to make them look like they are in scale.  I just bought an N scale train set and the lettering is 'way out of wack, but it looks appropriate at the smaller scale because of what it suggests to our eyes.  I find that I also adjust for color when working smaller -- usually toning the value down considerably.  So, instead of black, I might use gray for example. I wonder if you make these sorts of scale and color decisions or compromises for your wonderful dioramas, too.  Thanks for the tips.

big train: Thanks for the basic formulas for when I'm too lazy to log in to a computer (which is most of the time after 8-hours in front of one).  And an excellent observation about the converter rounding up and hiding the underlying and easier to manage correlations to inches.  It is good to know that 1/4' = 1'-0" is a common drafting scale should I ever get so inspired as to scratch build a (cardboard) building.

Fun stuff, guys.  Thanks for your comments.

Tomlinson Run Railroad

My "favorite math problems" to solve?  

I don't believe I will be accused of overstatement if I emphatically state I've never had a favorite math problem.

Curt

Other than basic arithmetic, over the years I've used plane trigonometry the most.

History does not bear out your assumption that they are on different tracks.

"Plane" as in air  plane? :-). Last time I used that math form was in a college class, likely on a surface archaeology survey I did with a geology major.

I can see plane trigonometry coming in handy for measuring the height of a prototype engine or building, and perhaps figuring out complex roof angles, and where they join. Some tricky track curves?

Lately it has been V=IR and W=VA...

Everything electrical...

Plane trig as opposed to solid or spherical trigonometry.

You are right. Building a layout is nothing but a long series of those dreaded "word problems" from math class once upon a time!

I find that I am doing fractions in my head constantly... If I need 2 3/4 on the outside of the curve, and I have 5 5/16 to work with, then the center needs to be how far from the other side? Ok, so the least common denominator is...

There are lots of occasions to use basic geometry: how long a train can be turned on this reverse loop? Let's see, C= D*Pi... I want to cut a corner brace for the bench work...how long to make it? Well, a^2+b^2=c^2, so... They taught us in school how to find square roots; I wish I'd learned that better. I hate stopping what I'm doing and fumbling around for a calculator...I've already got a pencil in hand!

I have many times wished that I'd worked harder in Trig class in high school. For example, building a control panel: I know the size of the panel, and how tall the back of the panel can be; what angle do I cut on the sides? No clue....  I built a section that swings out: If the section is 33 inches wide, and 9 inches deep, then how much clearance will I need so the rear corner does not hit the frame when I try to open it? Umm, I guess I can build a mock-up out of cardboard first...  This is a 3.5% grade, and I want to make some supports for it. What angle do I set the crosscut fence on my table saw? Maybe I'll cut them long, so I can keep trying different angles till I find the right one...

And we used to complain that we would never use this stuff for anything! if any of our young members who are still in school are reading this, please, do yourselves a favor and learn your math !!! 

TomlinsonRunRR posted:

when will they meet?  Answer: never, they are travelling on separate tracks!   But seriously, it is amazing how often I think of this high school math problem when I hear a train whistle, as I just did for the Boston to Fitchburg MBTA commuter train at the ungodly hour of 7:05 AM on a Sunday.  Really, who needs to get to either location that early??  (A few minutes later, I heard the second train so I didn't even need to sharpen my pencil).  Being math challenged, I never appreciated that problem at the time, but as I say, I often think of it now.

Question: How many ways do you find yourselves using math as modelers, electricians, layout builders, rail fans, or engineers; and what are your favorite math problems or solutions to solve?  Which ones do you grapple and struggle with but plow through to the bitter end because you need to?  Or do you just say "what the heck? It's good enough for rock and roll" and wing it?  Measure twice and cut/snip/solder or only once?

Personally, I'd like a nice formula for converting 1:1 measurements into 1:48 when I want to model something that scales down to values smaller than a quarter of an inch.  If it isn't divisible by two, it makes my brain hurt to try and convert to something less than a foot. (For example, the colored metal commuter rail signal flags.)  if I had a nice formula, I could write a computer program to do it for me and avoid the risk and mess of my brain exploding. And then there are my civil engineer great uncle's rulers in divisions of 10s, 20s, and 50s that I cherish. I'm sure they'd come in handy if only I had a clue ...

Tomlinson Run Railroad: where we love applied mathematics, we just can't apply it.

 

Take this course???

Modeling Complex Motions and Simulating Reality with Overset Mesh

Bogie

phillyreading posted:

never do I algebra which I took in 12th grade...

As a Scoutmaster, I found myself teaching Scouts basic algebra on numerous occasions. INTENDED as humor, the boys always remembered this....

At work, the equation of a straight line and Ohms Law are SOP.

OldBogie posted:

Take this course???

Modeling Complex Motions and Simulating Reality with Overset Mesh

 

Bogie

LOL!  The more I think about it, I "simulate reality" enough already with my overactive imagination!  This would only encourage  me ... oh yeah, except for the complex math ...

J Daddy posted:

Lately it has been V=IR and W=VA...

Everything electrical...

Ah, thanks for the fine contribution from the electrical end of the hobby, J Daddy.  I haven't needed Ohm's law yet but W=VA has come in handy more than once.

Gilly's reply about Ohm's law and linear equations led to this intetesting web find on non-linear conduction. Who knew?  OK, probably all of you "wicked smaht" guys ... I'm not sure if there's a real world/model application here, but it was an interesting read about the effects of heat, gasses, and etc. on resistance:

http://www.allaboutcircuits.co...onlinear-conduction/

(As a kid, something like a million years ago, I tried to teach myself basic electronics by reading my father's WWII elctronics manuals. Perhaps he had them because he was an X-ray machine instructor?  The Army's Socratic training method in use at the time was lost on me.  It made for a tough slog with those interminable Q&A interuptions.  So a clear and well written article like the one above is a welcome find.  Maybe I'll look for those old books and try to read them again with new eyes, old age reading glasses, and model RR-focused inspiration? :-)

TRRR

Gilly@N&W posted:

phillyreading posted:

never do I algebra which I took in 12th grade...

As a Scoutmaster, I found myself teaching Scouts basic algebra on numerous occasions. INTENDED as humor, the boys always remembered this....

At work, the equation of a straight line and Ohms Law are SOP.

I think the example is slightly incorrect, I was taught different.

Think it was some guy named Timothy who said "The love of money is the root of all kinds of Evil" which changes it to "Girls who love money = All kinds of Evil"  rather than "All girls are evil"

Substitute "model trains"for "girls."

Gilly@N&W posted:

A necessary evil none the less!

Jerry 

RJR posted:

Substitute "model trains"for "girls."

And if you dabble  in HO scale, the formula becomes "The square root of all evil ..."? 

(She who has her eye on some new items suitable for the HONGZ post ...)

Since there are some persons, who must be under 40 to see the trains, run even smaller gauges.  So now we get into even higher math:  cube roots and "4th" roots.

Oh no!  The affects of the hobby are exponential! :-}  (But we knew that ...)

>> Yikes! That post should read "effects" ... oh what the heck, let's just say both apply ...

They meet on the bridge, Gomez is running his trains again

OP, they meet n Chicago, had this quiz in school.9:35 am ct

I use math quite a bit. Aside from calculating to scale up/down equipment from different scales, I use trig quite a bit to determine curve module sizes for various arcs/radii and appropriate curves/tangents to achieve an S-curve offset, etc.

By the way, the call of the question usually reads something irrelevant to the fact pattern like "who's working the grill at Pat's Steaks in Philadelphia?"

J Daddy posted:

Lately it has been V=IR and W=VA...

...

W=VA vs. W= E^2/R, ("E" being equal to IR, so the equation also translated to (IR)^2/R) used to bug me. W=VA was simpler and pretty accurate, but they always told me there was some "technical" difference.

RJR posted:

Substitute "model trains"for "girls."

Well, you're gonna have to because most people with one rarely have the other as well!

AGHRMatt posted:

J Daddy posted:

Lately it has been V=IR and W=VA...

...

W=VA vs. W= E^2/R, ("E" being equal to IR, so the equation also translated to (IR)^2/R) used to bug me. W=VA was simpler and pretty accurate, but they always told me there was some "technical" difference.

AGRMatt

There is a difference between Watts and VA. When the circuit load is a light bulb or other purely resistance device then  power (Watts) = VA, but when you introduce capacitance or inductance to the circuit there is a phase shift between current and voltage and now power does not = VA. At best Watts = VA. VA is always = or > Watts. The utility companies prefer watts = or near VA.

Oman posted:

AGHRMatt posted:

J Daddy posted:

Lately it has been V=IR and W=VA...

...

W=VA vs. W= E^2/R, ("E" being equal to IR, so the equation also translated to (IR)^2/R) used to bug me. W=VA was simpler and pretty accurate, but they always told me there was some "technical" difference.

AGRMatt

There is a difference between Watts and VA. When the circuit load is a light bulb or other purely resistance device then  power (Watts) = VA, but when you introduce capacitance or inductance to the circuit there is a phase shift between current and voltage and now power does not = VA. At best Watts = VA. VA is always = or > Watts. The utility companies prefer watts = or near VA.

Thanks.

Where do you bury the survivors ??

If a Pennsy GG1 is going due east at 20 mph in the shadow of a building 10 stories tall with a wind whipping around it in a clockwise direction at a speed of 40 mph, which direction is the smoke going to blow from the engine and at what speed?

If a Pennsy GG1 is going due east at 20 mph in the shadow of a building 10 stories tall with a wind whipping around it in a clockwise direction at a speed of 40 mph, which direction is the smoke going to blow from the engine and at what speed?

I've never seen smoke coming out of a GG-1. They are electric.

C W Burfle posted:

I've never seen smoke coming out of a GG-1. 

Sure they do...

Jerry

CQ, they could make smoke even when not burning, since (with one exception) they had oil-fired boilers for train heat steam.

I can't answer this question. I still haven't figured out the one. Do you take the bus or work in an office..

The answer I get is " Engine not found " 

There is a difference between Watts and VA.

In line with the seriousness of this thread, I would point out that there is a greater difference:  Watts is an area of Los Angeles; Virginia (VA) is as close to heaven as one can find on this beautiful planet.