I understand the average walking speed of an adult is about 3 miles per hour.
If I am walking along the layout's edge at the same rate of travel as my train, at what scale speed would the train be running? Thank you.
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That would be 264 feet a minute. A scale mile is around 110 feet. So you'd be doing about 144 scale MPH. 
This got me thinking. Time isn't scalable, but you are not scaling time here- it is constant. You are only scaling distance.
So I did a test. I marked out 10' and then walked it a regular pace. It took about 3 seconds. If I multiply that times 1200 I get an hour. So multiplying 10' x 1200, I would walk 12,000 feet at that pace in an hour. Divide by 5280'/mile and I was walking about 2.27 mph.
Now if the train travelled the same 10', multiply that time 48 and it went 480 scale feet. Multiply that my 1200 and divide by 5280 and you get 109 MPH. And I suspect that you weren't even walking at 2 MPH, because that is a brisk pace indoors, so you train was going somewhat under 100 mph.
It doesn't seem to be going that fast because if your eye is 4' from the train, that is like almost 200' in O scale, and speed is less obvious at a distance. Try setting the train's speed at your walking pace, and then take a video with the phone as close to the track as you can, and you will see how fast it is going.
5280 feet in a mile. 48 scale feet in 12 inches.
5280 divided by 48 is 110 real world feet in a scale mile.
Figure out 110 feet of distance on your layout.
If you do that distance in a minute, that's 60mph.
Time is the same regardless of scale.
A guy who can figure out all that curved bench work should be able to figure it out....and there is no such word as cabeese, it's cabooses. 
Simon
@Simon Winter posted:5280 feet in a mile. 48 scale feet in 12 inches.
5280 divided by 48 is 110 real world feet in a scale mile.
Figure out 110 feet of distance on your layout.
If you do that distance in a minute, that's 60mph.
Time is the same regardless of scale.
A guy who can figure out all that curved bench work should be able to figure it out....and there is no such word as cabeese, it's cabooses.
Simon
Yup. To expand on that for smaller layouts.............................
Divide 110 feet by 10, and you get 11 feet. Divide 60 seconds (1 minute) by 10, and you get 6 seconds. So, mark off 11 foot on your layout, then time a train running that 11 foot distance (a stopwatch works best). A train running that 11 foot distance in 6 seconds is doing 60 scale miles per hour.
You can do further calculations from there. A freight train running the 11 foot distance in 12 seconds is doing 30 scale miles per hour. A crack passenger train running that 11 foot distance in 4 seconds is doing 90 scale miles per hour. And so on and so forth.
With a calculator, you can quickly make up a chart with 10 smph (scale mile per hour) increments, or 5 smph increments, or whatever increments you desire. And so on and so forth.
Keep in mind this is for 1/48 scale. If most of your trains are traditional-sized (approx 1/56 scale) or O27-sized (approx. 1/64 scale), you may want to re-calculate everything based on the relative scale size of you your trains. If you're really picky, that is. Otherwise, 1/48 would probably suffice. Sorta' kinda'.
Just another way to have fun with trains. 
So, if two trains are headed toward each other and one train is going 100 smph and the other is going 75 smph, how many scale boxcars does it take to make a real mile? 
Less-math-involved method:
Number of inches traveled in 2.5 seconds=O scale MPH. Done
---PCJ
If you don't want to do the math I did it for you. If your clocking O scale measure out 110' that is 5.75 laps around a circle of O-72. If you are surprised and things seem slow to you remember 1 real MPH is 48 scale MPH in O scale. Attached jpeg and doc versions. j
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@Tom Tee posted:Simon, After reviewing the differing responses from some of the best OGR minds can you see why I put this question out to the greater field?
Because you're into SM? You were looking for a few laughs? To paraphrase Forrest Gump: You ask a question on this forum and you never know quite what you're going to get as an answer? Can't be April Fools...wrong date!
Simon
This is about 53 feet of track. At scale speed of 60 MPH it should take close to one minute to go around twice. That seems painfully slow when I actually do it.
Does time change too?
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Like I said, he's smokin' along the tracks.
FWIW, I walk 10 feet at a normal indoor walking pace in about 2.4 seconds, I timed it a few times and took an average. If a train was running along side me at that pace, it would be moving at 136 scale MPH.
My original calculations seem to be correct.
Tom, this is a good discussion. An eye opener for realistic scale operation.
@GVDobler posted:This is about 53 feet of track. At scale speed of 60 MPH it should take close to one minute to go around twice. That seems painfully slow when I actually do it.
Does time change too?
No. The time does not change.
Get a 1/48 scale figure, and place it next to the track. Turn your train on, set it for 60 scale mph, then get right down there with the 1/48 figurine and eyeball the train as it goes past. Can you see (imagine) the train thundering past at 60 mph?
On the flip side of the coin, stand 100 feet back from a 60 mph highway, and note how fast the traffic seems to be going. Then, jump in your vehicle, and drive 48 time further away (4800 feet, almost a mile). Get out of your vehicle, watch the traffic, and note how fast it seems to be going. Does it look like it's going at a snail's pace, compared to before?
Time is constant, no matter what the scale speed & distance is.
If your accustomed to seeing how fast your 2037 can make it around an oval of track on a four by eight sheet of plywood without jumping off the track then scale MPH is going to seem painfully S-L-O-W. However it is your railroad run it as you see fit.
I think it might be fun to have a large switching layout and set up complicated switching scenarios and see who can solve the problem fastest no speed limits. Better yet two layouts side by side. Maybe we could sell tickets. j
@Mixed Freight posted:Time is constant, no matter what the scale speed & distance is.
Good answer on the time and distance, a great way to visualize the difference. I know when I crank MTH stuff to 60 scale MPH, it seems like it's flying!
@JohnActon posted:I think it might be fun to have a large switching layout and set up complicated switching scenarios and see who can solve the problem fastest no speed limits. Better yet two layouts side by side. Maybe we could sell tickets. j
We could charge extra for each crash. 
@eddiem posted:So, if two trains are headed toward each other and one train is going 100 smph and the other is going 75 smph, how many scale boxcars does it take to make a real mile?
I see you and I had the same math book in elementary school.
In answer to the question:
- Determine the distance covered by the locomotive in 1:1 feet, then multiply it by 48.
- Divide that distance by the time taken to cover it and that gives you the velocity in scale feet per second.
- Multiply that by 3600 for scale feet per hour.
- Divide that by 5280 and you'll have the scale miles per hour.
An O scale mile is 110 feet. A train covering that distance in two minutes is traveling 30 scale miles per hour which is about the fastest I like to run on the club layout. However, running a nice slow freight at 15 scale miles per hour allows you to appreciate the interaction between the train and the scenery.
The math doesn't lie, they're really going that fast, at least in scale MPH.
You have very fast eyes.
@Tom Tee posted:John, agreed, nothing beats truth, facts & reality but what about the lack of a side rod blur?
Depends on what size the driving wheel diameter is. i.e., Smaller drive wheels will spin faster at 60 smph, while larger drive wheels will spin slower.
Typically, Steam engines meant for freight service had smaller drivers, so they could drag heavy freight trains along, but at slower speeds. While on the other hand, steam engines in passenger service tended to have larger drivers, so they could go faster. But larger drivers also limited the tonnage they could pull. Remember, a larger wheel will cover more distance in one revolution than a smaller wheel would. If both wheels turn at the same rpm, then the larger wheel will go further, which equals faster than the smaller wheel.
Model trains however, can out-perform full size trains. For instance, you can run a 2-8-2 Mikado with smaller drive wheels (typically a freight engine) at 90 smph, and the side rods will be a blur. Which may look fine to some, but others with an eye for scale fidelity would probably cringe. If a real Mikado could get up to that speed, the entire valve gear assembly would explode in short order from all that centrifugal force. Ouch!
