How fast is your train running? Do you know?

[ginzokid]

I ran across an interesting article yesterday in an old magazine of mine about how to make a "Speed Trap" for your trains to determine the scale speed. I can't believe how simple it is. The formula I'll give you in a minute looks weird, but it somehow takes into consideration the coefficient of friction. Don't ask. Just plug in the numbers and it works. How to make the "Speed Trap": Measure off a level straight section of track a minimum of 2 feet long and mark it with "mile posts" or something. The longer the section you can measure, the more accurate the figures will be. (I am fortunate enough to have a 6 foot section to use.) What to do: Run your train through the "Speed Trap" at the speed you feel is "right" and time it with a second hand or stop watch if you have one. Be sure the train is running at speed before it gets to the measurement area. The Formula: Take the measured distance and divide it by the seconds it took to traverse it. This will give you Feet/Second. Now Multiply this figure by 59.3. The result will be Scale Speed in MPH. The scale of your trains does not matter. The same formula works for all scales. Here are some of my figures. I ran the 2-8-0 through at 9 seconds which gave 6ft/9sec = .666 f/s x 59.3 = 39.5 smph. A 12 second run gave; 6ft/12sec = .5 f/s x 59.3 = 29.6 smph. The Shay and Climax were both run through at 25 seconds; 6ft/25sec = .24f/s x 59.3 = 14.2 smph. I next took a 4 foot section of my N scale test track and tried it with the only N scale engine I have, the Shay. Was I ever off on that one! First run was 5 seconds or 4ft/5sec = .8f/s x 59.3 = 47.4 smph. For a Shay, that was "Rocket" speed. Second run was 15 seconds or 4ft/15sec = .26f/s x 59.3 = 15.8 smph. Now that is better and you can see the comparison between both scales at the slower speed. Just for kicks I figured out the length of time it should take for "A mile a minute" in a 4 foot run; 3.95 seconds. Have fun with this guys and how about reporting any results you get. I learned to slow my trains down. What will you all learn... The Codfadda B-) Try it guys. I think you will find that what you "feel is right" might be a bit fast.

[beastranger]

Good one CF! Will definatly have to try that one out. You could even figure out how long your mainline is (in miles) by setting your speed to say 60mph and timing it . Punk

[untabubba]

Pete, That is VERY interesting! Can't wait to try it! I don't understand how it could work for all scales!?! How come there's no taking size into account? I mean, 2 feet is WAY different for N and O, for example. (320 vs 96 scale feet.) I'll call my Physics teacher buddy. Maybe he could explain it and I could relay the explanation to the group. Marc

[ginzokid]

Marc, It's all about time and distance. Size has nothing to do with it. Think about it. A car or a horse going 40 mph is still going 40 mph. Look at my trials again. The On30 took 25 seconds to cover 6 feet for a speed of 14.2smph. The N scale Shay took 15 seconds to cover 4 feet for a speed of 15.8smph. The speeds are similar even though the time and distance covered are different. So the formula takes care of the scale difference. The two run side by side would appear to be going a close speed but the distance covered would be different. BTW, the article was written by a mechanical engineer, thus the coefficient of friction being taken into consideration. B-)

[untabubba]

OOOOH! DUH! Marc (who did not do well in physics!)

[crazyd37]

Thanks for the info Pete! DZ

[dl85vette]

I sort of agree with Marc on the scale.Due to perception the speed seems to be fast for the scale. I think the formula itself is correct pete as far as actual real life speed, but to correct for scale perception I think ya should mark off the speed trap in scale feet for applicable scale. I think then the result would be a 'scale speed'. Does this sound correct? Dave Need 4 Speed

[ginzokid]

Dave, Think about this. My N scale example of 5 seconds for an actual 4 feet would work out this way if we folow your suggestion. 4 real feet x 160 (N scale) = 640 feet traveled in the 5 seconds. You can't change the time to scale. 5 seconds is 5 seconds. With me so far? Plugging into the foumula: 640/5 = 128 feet/second x 59.3 = 7,590.4 scale mph. A review of the original formula way: 4 feet/5 seconds = .8 f/s X 59.3 = 47.4 smph. Now do you believe the formula? B-)

[untabubba]

I got a headache! Mr. B

[nascarpetlover]

Isn't that the same method used in figuring the price that is charged for gas these days?? LNF PS If not then I also have a headache.

[ginzokid]

Take two asprin and call me in the morning..... B-)

[dl85vette]

Make a math dummy outta me :P Unless....pull the motor out and replace it with a motor from a dentist drill hydraulically coupled to the trucks for smoother transition. Watch that L/L gp38 go !!! I wanna see someone put several hundred feet of track down in their yard and install a model rocket engine in the chassis and light it off. Dave sun-burned my back yesterday,think it went to my brain

[untabubba]

When I was a kid I used to have a quarter mile strip set up for my Aurora HO AFX race cars. I got to screwing around with the gear ratios and slick sizes. I had them going, like, 400 scale MPH! (I got your rocket car.....RIGHT HERE!! ;\ ) Mr. Breeze

[ginzokid]

Back in the olden days, yarn ago, when I was a kid for the first time, we had Jetex Cars which we made out of wood and wheels from Pine Cars parts and wheels and then we strung a line of kite string down the road. The cars had two u-shaped staples under them which the string was thread through. Then we attached the Jetex engines to them and lit them off. These were really solid rocket fule motors and got so hot they melted the tar on the road if they flipped over. Most of them would easily run a half mile. That, my friends, is one heck of a lot of string! BTW, we are talking the late 50s, early 60s. These were also used to power gliders, which usually burned up somewhere along the way. But, boy, we sure had fun! B-)

[untabubba]

Pete, That sounds like a BLAST!!!! (PUN?) Seriously, that's some neat "kid fun" right there! Sounds like a scene from one of those nostalgic period movies like "The Christmas Story". (About the kid that wants the BB gun) We used to send our "unwanted" airplane or cars models down the hill with firecrackers taped to them. That's destructive on purpose, but how do you think special effects guys are "born"! ]:) Marc