I have got to admit that carrying the answer out past 2 decimals is a bit off the wall.
Bear "It's all about having fun."
I had two well marked points 60" apart on the old layout. I used these to calculate scale speed with a target of 30 MPH for normal operation.
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I was amazed at how slow that was! I ran trains way too fast for too long.
-Kevin
Living the dream.
Graham LineLet's approach it another way. If a 50-foot box car (HO scale) takes two second to pass a fixed point on the railroad, how fast is it going?
(50 ft / 2 sec) * (3600 sec / hour) * (mile / 5280 ft) = 17 mph
1 mph 17.6 in/sec 0.2 scale in/sec 5 mph 88.0 in/sec 1.0 scale in/sec 10 mph 176.0 in/sec 2.0 scale in/sec 15 mph 264.0 in/sec 3.0 scale in/sec 20 mph 352.0 in/sec 4.0 scale in/sec 25 mph 440.0 in/sec 5.1 scale in/sec 30 mph 528.0 in/sec 6.1 scale in/sec 35 mph 616.0 in/sec 7.1 scale in/sec 40 mph 704.0 in/sec 8.1 scale in/sec 45 mph 792.0 in/sec 9.1 scale in/sec 50 mph 880.0 in/sec 10.1 scale in/sec 55 mph 968.0 in/sec 11.1 scale in/sec 60 mph 1056.0 in/sec 12.1 scale in/sec
greg - Philadelphia & Reading / Reading
Let's approach it another way. If a 50-foot box car (HO scale) takes two second to pass a fixed point on the railroad, how fast is it going? What "scale speed" does that represent?
I assume of course that no one is actually trying to time a train travelling only 1 foot...at least not if it's going fairly fast! The longer the sample area, the more accurate the result, so setting up something at least say 6' long and working from there would be better. As it happened (not planned), my old layout's continous loop worked out to (IIRC) 997 meters, so was easy to treat that as one kilometer and time how long it took the train to travel the 1k. and figure the speed from that. 1 min. = 60 kph, 2 min. = 30 kph, etc.
I suppose easiest of all is to use an engine that "talks" and tells you it's speed by pressing the correct function button. Several of my old BLI engines have that, not sure if the newer ones still do that?
I keep one online calculator in my iPhone and iPad. Does not get any easier.
Google has always been a great help.
I remember pre-Google and going to a local library for back issues of Model Railroader and looking up info. Today we have it so easy.
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
Mister Mikado Example: 60 miles per hour is 88 feet per second. For the HO scale equivalent do I divide that by 87? That's ~ one foot per second. Thanks! An easy rule of thumb I use is that a 40 foot car will pass a fixed spot in one second when travelling 28 mph. A 50 foot car will pass a fixed spot in one second when travelling 35 mph. You can easily to the math for additional seconds, 80 foot cars, etc. I found this on a table on the back of a Staten Island Rapit Transit Employee Timetable.
Example: 60 miles per hour is 88 feet per second. For the HO scale equivalent do I divide that by 87? That's ~ one foot per second.
Thanks!
The number of inches travelled in 5 seconds in HO is equal to the MPH the train is travelling at, therefore 12 inches per second is equal to 60 inches in 5 seconds.
I have a number of spikes in the middle of a section of track at 5 inch spacing to represent survey pegs. They have a light coat of white paint so when I start at the first one, I count 5 seconds and check the pegs I have passed. 7 Pegs = 35smph and I can guess the fraction between markers.
I have a fuller explanation on a web site http://www.xdford.digitalzones.com/modelrr10.htm which covers other scales using the peg method...
Hope this helps
Cheers from Australia
Trevor
Reminds me of the discussion of significant figures in my college physical chemistry class several milennia ago.
Joe
rrinker richhotrain ROBERT PETRICK Okay, but if you guys are gonna pick nits, I'd point out that the HO scale factor is 1:87.1 . . . or thereabouts. Carry on. Robert Thereabouts, 1:870857142 to be precise. Rich Silly people, mixing metric and English measurement in the same scale. (3.5mm to the foot). Also can I borrow your electron microsope to see a scale that small? Sure you mean 1:87.08571428606 (I found a calculation of 3.5mm to inches that gave me enough decimal places to actually go that far out) Over my 25 foot wall length, this extra bit after the 87 means I can run a whole 2 extra scale feet of track. --Randy
richhotrain ROBERT PETRICK Okay, but if you guys are gonna pick nits, I'd point out that the HO scale factor is 1:87.1 . . . or thereabouts. Carry on. Robert Thereabouts, 1:870857142 to be precise. Rich
ROBERT PETRICK Okay, but if you guys are gonna pick nits, I'd point out that the HO scale factor is 1:87.1 . . . or thereabouts. Carry on. Robert
Okay, but if you guys are gonna pick nits, I'd point out that the HO scale factor is 1:87.1 . . . or thereabouts.
Carry on.
Robert
Thereabouts, 1:870857142 to be precise.
Rich
Silly people, mixing metric and English measurement in the same scale. (3.5mm to the foot). Also can I borrow your electron microsope to see a scale that small?
Sure you mean 1:87.08571428606 (I found a calculation of 3.5mm to inches that gave me enough decimal places to actually go that far out)
Over my 25 foot wall length, this extra bit after the 87 means I can run a whole 2 extra scale feet of track.
--Randy
So noted, so edited.
Alton Junction
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
There are speed calculators online.
Below is one.
http://www.stonysmith.com/railroad/speedcalc.asp
Edit Note: Oops, I missed the decimal. It is there now.
And if you want to be even MORE accurate in your approximate calculations...HO is 87.1 rather than 87.
I actually have a chart up on the wall for calculating s[cale]MPH on the fly. Just pick two points where you know the distance and time the nose of the locomotive between those two points. Glance up on the chart to find its time and you get a fairly accurate approximation of how fast your train is going in sMPH. I calculate it using the following formula:
[ft/sec] / 5,280(ft/mi) x 3,600 (sec/hr) x 87.1 (HO) = [sMPH]
Tom
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.
LINK to SNSR Blog
In HO, one scale mile is 60 feet. I know that's not exact but close enough for government work. So one foot per second means 60 feet per minute or a mile a minute. That's 60 mph.
Sir Madog This is what I like about participating in a forum - you get at least three answers to your question, all different, none of them wrong!
This is what I like about participating in a forum - you get at least three answers to your question, all different, none of them wrong!
For HO scale, one foot per second is well within the allowable error for automotive speedometers. I have posted this a few times on this forum.
Chuck (Modeling Central Japan in September, 1964 - all measurements metric)
You can always find a conversion program on-line. Plug in the appropriate numbers and voila, instant answer.
Mister Mikado Example: 60 miles per hour is 88 feet per second. For the HO scale equivalent do I divide that by 87? That's ~ one foot per second. Thanks!
Since 60 MPH equals 1 mile per minute, and since there are 5,280 feet in a mile, the HO scale conversion is 5,280/87=60.69 feet per minute, or 1.0115 feet per second (60.69/60).
Let´s see -
1 mile equals 5,280 ft.
A train travelling at 60mph therefore travels 60 x 5,280 ft = 316,800 ft.
1 hour equals 3,600 seconds.
316,800ft. / 3,600 seconds equal 88ft./sec.
An HO train doing 60 scale mph therefore should travel 1.010333ft/sec.
I guess you are correct!