Do I multiply the distance of of the track by 87 and divide it by the time it takes to complete the run? Is it totally different?
Respectfully,
Jacob
That’s exactly how I do it. My distance was measured with a carpenter’s steel tape in feet Time with a stop watch in seconds. To get the answer to come out in miles per hour I converted feet to miles (5280 ft/mile) and seconds to hours (3600 secs/hr)
Yes, for HO scale. If your loco goes 10 real feet in 10 seconds, that’s 870 feet in HO feet per 10 seconds (time does not scale). 870 feet is .165 of a mile, in 10 second. Times 3600 seconds in an hour is 59 scale miles per hour.
real feet/second x scale feet/real feet x 1 scale mile / 5280 scale feet x 3600 seconds / hour = speed in scale MPH
If you write it all out you will see that all the units cancel each other out except for scale miles / hour - this is how you know you did the math right!
–Randy
Here is a much easier way to pretty closely estimate your speed if you are lucky enough to be in HO. HO scale is 87 to 1. Now it just so happens that 60 miles per hour = 88 feet per second. Somewhere on your layout, on a good viewing point pick out two objects that are an actual foot apart. If the front of your loco ( or any other point on your train!) covers that foot in 1 second you are doing 60mph. 2 seconds = 30mph 3 seconds = 20 mph, 4 seconds= 15mph, 5 seconds=12mph, 6 seconds= 10 mphtherefore 10 seconds=6mph and 12 seconds= 3mph. After you get used to it you can even use 40’ freight cars (2= aprox 12") past any object. Happy railroading!
If your like me and don’t like math you can go to http://www.mcr5.org/articals/speed.htm and you can put in your numbers and will calculate it for you.
Andrew
I just push a button and my GP9 tells me how fast its going, lol.
[:)]I just eye ball it[;)]
OLE’IRISH
I hit a function key and my QSI speaks to me in a voice…
I just look through the locomotive window at the speedometer…
Mark in Utah
Just a lucky break, came out that my mainline “loop” is almost exactly 1 kilometer, so if the train takes 60 seconds to make one full trip, it’s averaging 60 KPH, 120 seconds = 35 KPH, etc. From there it was pretty easy to work a chart with the various times and speeds, and convert the KPH to MPH.
Glad I was able to find this thread again. I knew that there were a couple of very simple formulas to calculate train speed. A friend of mine was asking about this.
I’m not a “rivet counter” but I enjoy operating locomotives at realistic speeds so it’s handy to have an easy “rule of thumb” available. I like for my locomotives to simulate that they’re moving TONNAGE so when I throttle up, the unit doesn’t take off like a Mustang GT burning rubber!
( However, a few prototype locomotives like EMD SW series switchers can take off fairly quickly, like a pickup truck, when running light due to the low gear ratios. I saw SCL SW9s do this years back… Still, this would be the exception rather than the rule with most diesel locomotives.
Cheers
My transformers have the scale mph on them. If I turn the dial to 20, the train does 20 scale mph. If I turn the dial to 40, the train does 40 scale mph and so on…
trainluver1
Hi Trainluver,
One thing to be aware of though.
The Locomotive motors from Athearn, LifeLike, Atlas, Bachmann, etc., in HO and N scales utilize different measurements of voltage and current to move and pull loads. For example, a typical Athearn Blue Box motor requires more voltage than a typical Atlas motor to move so the mph that you’re looking at on the transformer might not be reflecting the true scale speed of your locomotives.
I know that my Athearn SD9 (bought it in the late 1970s) will “fly” at about 100 scale mph if you turn the knob of my MRC Tech II 2500 power pack to the “65 mph” increment. This old, open frame motored growler [:(!] will outrun all of my newer units. Of course, this thing “eats” amps too! [dinner]
This is why John Colley, Rrinker and the other posters have been using the above formulas to accurately calculate scale speed. I’m going to be checking out the DCC websites to see if one of these companies offers a digital readout solution to scale speed.
(Joe Fugate, where are ya?)
Andrew, that’s a great web site you included, thanks
“Hey AntonioFP45”.
The fact is, it really doesn’t matter to me if the scale speed isn’t 100% right. I run my trains slow anyway, and can kind of guess at what would be 30, 40 or 50 mph.
I’ve got a friend that runs his trains really fast, and says that if he didn’t, it would be borin
As a kid I was in a model railroad train race, there were Lionel, HO, S Scale… I ran all three, ended up winning the Lionel race, It was a simple dual loops of track each contestant runs, I recall I derailed a long distance away, I had to rerail my loco, my opponent derailed also, and he was closer to his throttle, but I rerailed faster than him and got to my throttle the same as him, I wooooon.,…
prize a 50 dollar gift certificate to a local hobbyshop…I never used it, I dunno why…
See, first you get an HO sized marathon runner, then …
Naw, I’m just pullin’ your leg!
For HO, do, in/sec X 5.56=scale MPH
Now, how many of us run our trains way too fast?
Also many clubs use time compression when having operating sessions. Running a large layout at scale speeds would probably be somewhat boring.
Bob DeWoody
…and here I’ve been tryin to read the speedometer on the dash of the locomotive.