I have searched this forum for a speed conversion formula & haven’t had any success.
What I need to know is, how does one convert HO speed to real life speed.
For example, if a loco goes 20ft on an HO layout in 30secs what is the equivalent miles/hour?
Mathematicians to the rescue please.
The information that you’re looking for is on Page 81 of the September 2003 issue of Railroad Model Craftsman.
The formula for the calculation is: (note the decimal point at the very start)
.6818 X Scale Factor X Distance (in decimal feet) divided by Time.
Scale factors: O=48, S=64, HO=87.1, TT=120, N=160, Z=220.
This is an N scale sample from the article:
.6818 X 160 X2.0 feet =218.176 divided by elapsed time. If the time to travel the two feet was 4.32 seconds, then 218.176 divided by 4.32 = 50.5 scale mph.
The following table is given for HO s.m.p.h. over a distance of one foot:
SECONDS---------S.M.P.H.
59.39--------------------1
11.88--------------------5
5.94---------------------10
3.96---------------------15
2.97---------------------20
2.38---------------------25
Hope this is what you’re looking for.
Wayne
.
Click on here and you can calculate any speed.
… Or you could just count ties… It once was, if I remember correctly, if you counted the ties, standard spacing, a loco passed per second, that was your MPH… 1 tie per second, one mile per hour… Always worked for me… People who use operating schedules based on a timetable will sometimes (quite frequently) use a fast clock… The way it works is this (and I know this is a little off your point but bare with me), we know that an actual HO scale mile is roughly 60 feet in real time… That is 1 second real time equals 1 second scale time… For the sake of the operating schedules, you divide that scale mile by your time scaling factor… So, if you are running a 6:1 fast clock (to keep the math simple), then your scale mile becomes 10 feet rather than 60 (for timetable purposes)… So if you’ve traveled that 10 feet in what amounts to the accelerated minute, you are traveling at 60mph, or 1 mile per minute… Get the picture?? You may say, wait a minute, a scale mile is a scale mile which is roughly 60 feet for HO… However, the idea is once you start operating on the time table, you forget all about actual distance as your goal becomes to reach the destination on time, so not to interupt the timetable.
Jeff
[8D]
Thank you one & all. Information noted.
Knew there were folks around who are better at figures than I am.