I once saw posted on this newsgroup a speed table converting prototype speeds to HO scale... 60 MPH prototype equals so many feet covered over so many seconds.in HO.
Does anyone have that table at their fingertips?
Thanks/Carter
The "near enough" figure for H0 is one foot per second = 60 mph. (1.0115 feey per second)
Many modellers find this sort of speed excessively slow, due to there having become used to train set speeds 3 or 4 times this rate. Real train speeds in built up areas are probably much slower than 60 mph and the more realistic model speeds extend the time to traverse a layout, which has to be good! Realistic acceleration and braking rates built into controllers or DCC decoders will scare the stuffing out of drivers.
Make one yourself! A mile is 5280 feet long, either real feet or HO feet. The HO scale proportion is 1:87, so an HO mile is 60.7 real feet long. A train going 60 MPH goes a "mile a minute", so a 60 mph HO train goes just over 60 real feet in 60 seconds, or 1 real foot per second. 30 mph is half as fast as 60 mph, so an HP train going 30 MPH goes 6 real inches in 1 second. It is easy to ratio from this to get a spped table for any other speed you want. But a table is hard to use - your hands should already be full with a throttle, a timetable, and a bunch of way bills for the cars in your train. I like to use the rule of thumb of one car length passing a point in one second ("one Mississippi") gives a good speed for any train: Passenger cars are about 80' long, or about 1 real foot over couplers yielding 60 MPH Modern freight cars are about 60' long yielding about 45 MPH Steam era freight cars are about 40' long yielding 30 MPH
2-Bay coal hoppers are about 33' long yielding about 25 MPH Ore hoppers are about 22' long yielding about 16 MPH Gary Q
Take the desired speed in miles per hour and divide by 4.95 to get HO scale inches per foot. For example, 10 miles per hour / 4.95 = 2.0 inches per foot.
Here are a few speeds and corresponding HO scale speeds:
1 mph = 0.2 in/sec 5 = 1.0 10 = 2.0 20 = 4.0 30 = 6.1 40 = 8.1 50 = 10 60 = 12 70 = 14 80 = 16 90 = 18 100 mph = 20 in/sec
That's a pretty good rule of thumb which gives pretty good scale speeds for various classes of trains.
I bought a cycle computer and mounted it on a wagon.(car) Next I made a tiny sliver of rubberized magnet and glued it to an axle. Last, I cut a lontitudinal slot in the floor and taped the reed switch in it so that it was close to the axle. The wire needed shortening and I programmed the cycle computer for the full scale size. The European wagon I used is marginally small so the bicycle computer has to sit sideways at 45 degrees but it would probably sit in a US boxcar so as to be visible through the open door.
The wagon gives miles per hour, Km/hr, average speed, distance travelled (handy for measuring track distances), time, time for distance (stop watch), temperature, and several other things in French, depending in which buttons you push.
Measure the size you can accomodate and the size of the computer before you leave the bicycle shop as the sizes differ considerably. The bicycle shop owner didn't really seem to comprehend when I said I needed to measure the computer to make sure it would fit the wagon!
Oh, and the computer can still be used on my bicycle. :-)
Regards, Greg.P.
Carter,
Here is the formula to determine scale speed:
SF x Distance (SF=Scale Factor in HO=87) Smph=0.6818 x --------------- Time
Example: 87 x 10' = 870 / 10 sec = 87 x 0.6818 = 59.3166 or 59 Smph
You will need to measure a portion of your track in whole feet to determine the 'Distance'. Time how long it takes for the engine to travel from the start point to the end point. Then use the formula to compute the engines scale speed.
Fred Ellis
Apart from Greg Proctor's suggested method of determining model train speeds, all the other suggestions are needlesly complicated. If your HO scale model train covers one actual foot of distance in one second, it is doing pretty much 60 miles an hour, and from this you can work out times for all other equivalent speeds. These speeds are better shown on a graph than in a table. The actual timing distance on the layout should be at least two feet or more, one foot is perhaps too hard to accurately time over. For a timer, buy a cheap digital stop watch from your local chemist (drug store). Of course if you want something that is complicated, set up a couple of I.R detectors in the track at a suitable distance apart, and wire them to give a speed readout on a digital meter. Saw this done on a big layout in Melbourne a few years ago. No, I have no idea of the circuit arrangements. Regards, Bill.
"Fred Ellis" wrote in message news: snipped-for-privacy@stic.net...
For very little extra you can get a 'cordless' cycle computer, then you only need to mount the sensor on your wagon/car and the readout can be handheld, much easier to read. Keith
Make friends in the hobby. Visit Garratt photos for the big steam lovers.
Hi.
Running at scale speeds requires a little accustoming, but the results are rewarding. Once hooked on the subject, a fanatic attempt to modify every loco may emerge. Ie. Switching cars at less than 5 SMPH or running way freights at 25 SMPH within city limits.
There are many methods for speed determination beyond counting and charts depending on the accuracy desired. Some are very simple, while others a very complicated including computer programming.
The topic is discussed at length in "How fast does your train go?" on my site. Many methods and evaluations are presented with examples. Basically they all depend on measuring distance and time.
After some learning experience and feel, the measurements become less frequent and may only be used for demonstration or checking out a new loco.
For more details with methods and extensive discussion of problems and solutions, see first site below in "How fast does your train go?".
Hope this helps.
Thank you,
Budb
Author of:
MODELRAILROAD TECHNICAL INFORMATION
I haven't come across those - obviously time I visited a cycle shop again!
One sure way to operate at scale speeds is to install a video camera in the nose of one of your locos and then operate it based only on the transmitted image on a TV monitor. I've taken apart two of the X-10 color cameras and mounted one with its batteries in an HO E-9A, and and another in an HO F-7A, with the battery pack in an adjoining B-unit. Running at excess speeds is immediately apparent as the scenery rushes by at a dizzying pace. Gary Q
Some time ago (you'd have to search the NMRA magazine database to get which issue, but I seem to recall it was sometime in the late 80's) Model Railroader ran a construction article on building just such a "speedometer".
If I come across it I'll let you know. As I recall it was not all that complex, basically a variation on a digital clock, modified to calculate and diplay scale speed.
Don
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