Do you want to know what speed in miles per hour your trains are travelling (scale miles per hour)?
Note: This gives you an approximate speed only and some numbers may have been rounded up/down for ease.
You will need to mark out a set distance of track, of at least 3ft and have a stopwatch to hand (most mobile phone have a stopwatch).
Here is a revised easy to follow formula;
1. Take the set distance of track (e.g. 3ft).
2. Divide by the time taken to travel the 'set distance' (measured with a stopwatch).
3. Multiply by 3600 (the number of seconds in an hour).
4. Divide by 5280 (the number of feet in a mile).
5. Multiply by the Scale of the train (e.g. for 00 this would be 76 (from 1:76)).
The result with be the Scale Miles Per Hour.
So the formula is = SET DISTANCE / TIME X 3600 / 5280 X SCALE = SMPH
For Example: A 00 scale train taking 10.4 seconds to cover a set distance of 3 feet
So the calculation would be: 3 / 10.4 X 3600 / 5280 X 76 = 14.9 smph
TO RECAP
SET DISTANCE - is space between two points (e.g. 3ft )
TIME - The time taken to travel the SET DISTANCE by the train
3600 - is the number of seconds in an hour
5280 - is the number of feet in a mile
SCALE - is the scale of the train you are measuring
Common Scales
0 = 1:43.5, 00 = 1:76, H0 = 1:87, TT = 1:120, N = 1:148 UK, N = 1:150 US
As mentioned this is not an accurate calculation just an approximation.
Hope you find this formula of interest and a bit easier to use.
Martin