I’m trying to figure out a way to determine the scale speed of my trains. I haven’t researched this topic much yet… I guess I could just use some basic math to determine time traveled over a given scale-distance of track, convert it to scale mph, then mark the throttle position and label the speed. This would have to be done with every consist at several speeds (and again and again each time I switch out a loco). The other problem I see is the fact that this would only work for straight track… any curve or grade will change speed. I have plans for signaling on my next layout (don’t we all…) and I’d really like to not violate the speed restriction through that limited-clear signal. Any other ideas?
There have been several threads on this topic, once just in the past three or four weeks.
You can measure a scale distance and time the locomotive through the distance. Then do a speed calculation. There is also a commercial speedometer advertized in MR.
Generally, and roughly, an HO engine moving its coupler 12" in one second is doing 60 scale mph. That’s off the top of my head, and I hope I have it correct. Cars, we learned many years ago, cover 88’ per second at 60 mph, and since our scale is one part in 88 (okay, okay…87…whoopeee), you get awfully close.
-Crandell
I have thought about purchasing one of these.
http://www.ulrichmodels.biz/servlet/the-490/Speedometer-for-HO-and/Detail
I don’t know how accurate it will be.
I use a complicated method that works for me.
I use a measured track section and stop watch. I take three measurements and average the results.
A HO scale mile is 60.6 feet. Do the math.
Rich
For steam engines I count the revolutions of the drivers for a period of time and apply the following formula: 60/time x revolutions x diameter of wheel x Pi (3.14 is close enough)/ 1056 = speed. For example, 20 revolutions in ten seconds for a 62" drive wheel yields 22.12 mph.[:P]
If you are trying to figure HO scale speed over an HO scale mile , shouldn’t you be timing it in HO scale seconds?
Moving 1.467 feet per second = 1 mile per hour
Is that 1.47 real feet or scale feet?
[swg]
http://www.mcr5.org/NMRA/articals/speed.htm
I use it all the time. It’s really come in handy more times than I can count.[:D]
I use the brew method, start engine at point A, poop the top, if train gets back to Point A and I have half a brew left it is doing 30 sips per minute.
All kidding a side. I use a stop watch and a measured section of track.
In my case, 10 feet X 87 = 870 sFoot. Engine covers the 870 sFeet in 20 seconds. That equals 43.5 sFeet X 60 seconds X 60 minutes = 156,600 sFeet dived by 5200 = 30.115 sMPH.
Far as the gadget that Ulrich sells, that seems like it would be fun. When I was racing slot cars I built a devices that would time and figure the speed of the slot cars. There was a free down load for this.
I will add, if you have to buy on line, you will be hard press to find a better company than Ulrich Models to deal with! Steve has went way above any other on line store to fix problems!
Cuda Ken
given the tips in this thread, what speed should the train be going on a main line run? i know it would change depending on how long your train is or on a grade… but like on a flat section traveling around your main line…
I have been running the digitrax speed at about 55-60 depending on the loco… but visually it seems to be a good speed…
I guess to ask it another way, is there a standard speed (limit) that the locos are allowed to go? or should go on a mainline?
Most freight locomotives have a top speed of 75. rRarely do they go that fast. It depends on a multitude of factors such as terrain, curves, grades, and traffic volumes. It also depends on weather. If there is inclement weather and visibility is limited then they will lower their speeds for safety reasons.
Of course us modelors should not have to worry about weather conditions on our layouts. At least I hope not or you have some major problems.[swg]
This question comes up with a lot of the guys I know and usually turns into some what of a verbal brawl on exactly how fast trains should be running and how do you accurately know bla bla bla. At he club we have a few places known to be measured distances and just like the real railroad if you use the old time over distance = speed formula just like the real railroads did you can calculate the speed of the train. Do you think they carried those fancy pocket watches just for looks?
I found several site that sell fancy digital do dad you can mount to your fascia I guess at any given spot to tell how fast your trains are going. I guess when you have nothing left to spend your money on their something you can buy. I personally like the ahhhh yeah that looks about right method but I have to say I am considering switching over to Cuda Ken’s method a lot more enjoyable and after a few you won’t care anyway.
Here are a few links to site who offer speedometers for your model railroad and even one that tell you how to make one that fits in a gondola car. If I’m not mistaken didn’t the prototypes use something called a Dynamometer car for exactly checking things like this? Yeah there’s also a link for that too…lol
http://www.trainspeed.com/products.htm
http://www.greenwayproducts.com/buy_speedometer.shtml
THIS is a prime example of why I SHOULD have been paying attention in math class, instead of watching the duckies outside the window. [:D]
Excellent link my freind I just the calculator and it is very user freindly
Very simple solution I use, found it in an old employee timetable. A 40 ft car will pass a fixed point in one second when moving at 28 scale mph. A 50 foot car passes a fixed point on one second when moving at 35 scale mph. Any remaining math i.e for 80 foot cars, faster or slower speeds is pretty straight forward. Works in any scale from prototype to Z. Ken
I always rounded those figures off slightly, and come up with:
6 seconds for 40ft car to pass a switchstand (or similar point): 5 MPH (legal yard speed in many places)
5 seconds 6 MPH
3 seconds 10 MPH
2 seconds 15 MPH
1 second 30 MPH
As Ken points out, the formula works in all scales. What Ken didn’t point out is that scale switching speeds can seem agonizingly slow in the smaller scales, with the smaller scales being worse. Even in HO, I’d like to know how many actually switch their yards or spurs at 5 scale MPH. That means it would take over 15 seconds to back a car from just in front of the turnout into a 9" long spur. And another 10 seconds to pull the locomotive back out.
just my thoughts
Fred W
HI there, I have an article on Scale Speed calculation which MAY work for you on my web site. www.xdford.digitalzones.com . Some people have said they do not quite follow it so if you need clarification, let me know off list!
Regards
Trevor
on a coolish un typical December day for Australia!