# scaling for dummies?

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#### wtaylor3

##### Member
So I have taken quite an interest in using my machinist training to replicate the world in miniature, everything from engines, to locomotives to boiler powered workshops.

That being said when it comes to locomotives I cannot seem to find a simple explanation of the scale lingo the model engineers use. (3 1/2", 5", 7 1/4") how does the inch scale work? is it 7 1/4" = 1 foot? or am I way off base here?

Train scaling can be a huge and confusing topic but in model engineering we usually refer to the width of the track that is being used. The actual scale of the locomotive is then usually scaled to some rationa number that is near to the ratio of this width to the width of the full scale track width.
In the USA the most common full scale widths are standard gauge which is 56.5 inches between the rails and narrow gauge which is 36 inches.
For example:
When we speak of 7" scale running of standard gauge the actual scale would be 7 / 56.5 beu even this gets more complicated in the USA where model track widts of both 7.25 and 7.5 are used. Most often we just ulse a scale factor of 1:8 for construction and adjust the wheel spacing yo suit the local track. These are large ride on locomotives.

On a smaller scale, Gauge 1 refers to a track width of 45mm and in the USA we often just use 1.75 inches for scaling purposes. This results in approximately 1:32 scale locomotive that ran on standard gauge track or 1:22/5 for a narrow gauge prototype.

As far as model stationary engines, you can adjust the piston or flywheel size to suit your needs, and then just use whatever scale factor that works out to be. Does not have to be a whole number, although some howl when modelers do that.

The scale factor on model stationary engines seems to be more for convenience when talking with fellow modelers (ie:1/2, 1/4, 1/8,1/16 scale, etc), but nowhere is it written that you have to adhere to any particular scale when you build an engine, so keep em guessing.

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Thank you both,that does clear up my confusion quite a bit

Just a little humor on that specification.

The US Standard railroad gauge (distance between rails) is 4 feet, 8.5 inches. That's an exceedingly odd number.
Why was that gauge used? Because that's the way they built them in England, and the first US railroads were built by English expatriates.

Why did the English people build them like that? Because the first rail lines in Europe were designed and built by the same people who built the pre-railroad tramways, and that's the gauge they used.

Why did "they" use that gauge then? Because the people who designed and built the tramways used the same jigs and tools that they used for building wagons, which used that same wheel spacing.

Okay, why did the wagons use that odd wheel spacing? Well, when they tried to use any other spacing, the wagons were prone to breaking down on some of the old, long distance roads, because that's the spacing of the old wheel ruts.

So who built these old rutted roads? The first long distance roads in Europe were built by Imperial Rome for the benefit of their legions. The roads have been used ever since. And the ruts? The initial ruts, which everyone else had to match for fear of destroying their wagons, were first made by Roman war chariots. Since the chariots were all made to certain specifications for or by Imperial Rome, they were all alike in the matter of wheel spacing.

Thus, we have the answer to the original questions. The United States standard railroad gauge of 4 feet, 8.5 inches derives from the original specification (Military, as it were) for an Imperial Roman Army war chariot. But one "nagging" questions still remains. Why did the design of the Roman army war chariots incorporate that specific wheel base?

Answer: Because the chariots were designed to be just wide enough to accommodate the back ends of two war horses. So, the next time you are handed some oddball specification and you assume that some horse's ass was responsible for coming up with it, you may be absolutely right with your assumption.

wtaylor3 - no one has actually answered your question yet, so here goes!
The measurements you quote in your original post are all the gauge of the track the locos run on - 3.5", 5" and 7.25" - this is the distance between the rails. These gauges equate to roughly 3/4"/ft, 1"/ft and 1.5"/ft.
Hope this helps.
Tom

Just a little humor on that specification.

The US Standard railroad gauge (distance between rails) is 4 feet, 8.5 inches. That's an exceedingly odd number.
Why was that gauge used? Because that's the way they built them in England, and the first US railroads were built by English expatriates.

Why did the English people build them like that? Because the first rail lines in Europe were designed and built by the same people who built the pre-railroad tramways, and that's the gauge they used.

Why did "they" use that gauge then? Because the people who designed and built the tramways used the same jigs and tools that they used for building wagons, which used that same wheel spacing.

Okay, why did the wagons use that odd wheel spacing? Well, when they tried to use any other spacing, the wagons were prone to breaking down on some of the old, long distance roads, because that's the spacing of the old wheel ruts.

So who built these old rutted roads? The first long distance roads in Europe were built by Imperial Rome for the benefit of their legions. The roads have been used ever since. And the ruts? The initial ruts, which everyone else had to match for fear of destroying their wagons, were first made by Roman war chariots. Since the chariots were all made to certain specifications for or by Imperial Rome, they were all alike in the matter of wheel spacing.

Thus, we have the answer to the original questions. The United States standard railroad gauge of 4 feet, 8.5 inches derives from the original specification (Military, as it were) for an Imperial Roman Army war chariot. But one "nagging" questions still remains. Why did the design of the Roman army war chariots incorporate that specific wheel base?

Answer: Because the chariots were designed to be just wide enough to accommodate the back ends of two war horses. So, the next time you are handed some oddball specification and you assume that some horse's ass was responsible for coming up with it, you may be absolutely right with your assumption.
Before the civil war, there were all sorts of gages. Lincoln did an executive order to standardize them to a certain size. One of the problems that the south had was that they did NOT standardize and this caused them immense problems with train transportation.

Before the civil war, there were all sorts of gages. Lincoln did an executive order to standardize them to a certain size. One of the problems that the south had was that they did NOT standardize and this caused them immense problems with train transportation.
We need more of that type of thing today on everything from charging ports on our electronics and electric cars to many other areas where standardization would not harm the product but simplify our life. I have often wondered why the automobile manufacturers could not standardize a lot of car parts. For instance wheel mount lugs. Why should the bolt circle on Ford wheels be 1/8" different than Chevrolet wheels? The only reason is so that the manufactures have a captive aftermarket.

We need more of that type of thing today on everything from charging ports on our electronics and electric cars to many other areas where standardization would not harm the product but simplify our life. I have often wondered why the automobile manufacturers could not standardize a lot of car parts. For instance wheel mount lugs. Why should the bolt circle on Ford wheels be 1/8" different than Chevrolet wheels? The only reason is so that the manufactures have a captive aftermarket.
A captive aftermarket means more \$\$\$\$ for the builder - - - whenever did these companies say that they gave a rip about their buyers?
(Its all about \$\$\$ for me - - - NOT you - - - did you miss that memo (grin!!!)? - - - Welcome to capitalism - - - .)

A captive aftermarket means more \$\$\$\$ for the builder - - - whenever did these companies say that they gave a rip about their buyers?
(Its all about \$\$\$ for me - - - NOT you - - - did you miss that memo (grin!!!)? - - - Welcome to capitalism - - - .)
A friend of mind delivers parts for the local Import Motors. They sell Volkswagen as well as Mercedes. He is always telling me about how something like a windshield for a for a Volkswagen will cost \$150 and a windshield for a Mercedes will cost \$800. These are probably both coming from the same glass manufacturer.

We need more of that type of thing today on everything from charging ports on our electronics and electric cars to many other areas where standardization would not harm the product but simplify our life. I have often wondered why the automobile manufacturers could not standardize a lot of car parts. For instance wheel mount lugs. Why should the bolt circle on Ford wheels be 1/8" different than Chevrolet wheels? The only reason is so that the manufactures have a captive aftermarket.
Absolutely true. If, in the case of car manufactories, they were not so well intrenched in our national way of life, they might go out of business for such petty and trivial ways of doing. More recently than the beginnings of the car manufactories is the computer business. Many computer businesses had good shares of the market and great products but because of their greed they manufactured proprietary peripherals. Sometimes aftermarkets products sprang up. my favorite computer of all time was the Amiga 500 and they went out of business partly because of this but more because of faulty advertising and failure to update peripheral products.

When IBM decided to go open with their product, it helped to destroy a bundle of com,puteer businesses including the Amiga but created a new bundle of more standardized "IBM" clones. All that has developed phenomenally since 1990s into computers and computer like things that were unimagined at that time.

Just out of curiosity, I bought my Amiga in 1988. It was the best computer available until about 1995 when the clone wars finally caught up with the capabilities of the Amiga. I considered it a tragedy that Amiga did not upgrade and advertise better. They lasted longer in Europe than in the USA. Had they done a trick like IBM did, they might have been a dominant force in computerology.

A captive aftermarket means more \$\$\$\$ for the builder - - - whenever did these companies say that they gave a rip about their buyers?
(Its all about \$\$\$ for me - - - NOT you - - - did you miss that memo (grin!!!)? - - - Welcome to capitalism - - - .)
Actually, that's a very short terrm solution. Those types of business only last a while as they try to overcharge for their stuff and the customer simply goes eleswhere. Those people who lower their prices to something reasonable not only stay in business longer but make more \$\$ by LOWERING their prices because they sell more product. The first rule of economics is infact: lower hyour prices, sell more product and make MORE \$\$.

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A friend of mind delivers parts for the local Import Motors. They sell Volkswagen as well as Mercedes. He is always telling me about how something like a windshield for a for a Volkswagen will cost \$150 and a windshield for a Mercedes will cost \$800. These are probably both coming from the same glass manufacturer.
I had a couple Cadillacs at one time and the parts for Cadillacs were like that--very high. But gmc manufactured a model that was just below cadillac in luxury and cost. The frames of the two cars and manyh parts were identical so depending on th epart, one simplhy bought the cheaper brand. All the parts were manufactured in th e same plant. Simplyh A\$\$holes selling prestige to foolish bguyers. Franklyh that type of theft if simply disgusting.

I still have my TRS (trash) 80 over in the corner, which was actually my wife's computer when I met her in about 81'.
I recall running BASIC programs on it, using the color TV (cathode ray, not a flat screen) as a screen.

Sorry for the topic slide.

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Oh haha. My first was a trash 80. Ultimately it was the most expensive computer I ever bought.

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Or the command (while in EDLIN) to low level format your hard drive-

G=c800:5

Why do our brains remember these odd arcane snippets?

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graphics-based programs were a quantum leap forward, thanks to I think the Xerox PARC group, with the Alto that had a graphical operating sytem, and also the Xerox "Star" workstation.
Notably, some of the members of the new Apple computer company were former Xerox PARC programmers.
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Xerox had (arguably) a 10 year lead in what would become the 'personal computer' industry and utterly squandered it because senior management could only think in terms of photocopiers!! Steve Jobs attended a 90 minute tour/presentation in 1979 and then immediately focused Apple on developing a graphical user interface (funded by the profits from the Apple //). He recognized that the GUI was the inevitable future of computing whereas Xerox had been sitting on this for several years. Good summary of the story at:

https://www.mac-history.net/2010/03/22/apple-and-xerox-parc/
BTW, Apple made significant improvements to what they saw at Xerox. And made it all work on much less expensive hardware so that the final product was at a price point that at least some could reach. A Xerox Star cost something like \$40,000 in 1979.

Craig
(Gates, at Microsoft, was much slower to come around to the GUI.)

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