scale speed in HO

[edpb]

I have been learning how to program my American 4-4-0.  I have the loco on a 22 inch radius circle that I laid out a long time ago on a 4x4 piece of Homasote.  While I had the loco on that circle, I thought of calibrating the speed dial on my MRC Tech 6 control.  I got the loco going with the Tech 6 dial at 40 and timed one revolution and it took 26 seconds.  Using 87.1 for the scale factor, the speed came out at 26.3 scale mph.

Then I tried to translate that result into a simple calculation using just the time it takes to go around the circle, and I came up with 684 divided by the time around the circle in seconds is the scale speed in mph.

The next step was to realize that hardly anybody has a 22 inch diameter circle just lying around somewhere, so I went one step further and came up with this:

59.4 multiplied by any distance in feet divided by the time it takes to travel that distance in seconds is the scale speed in mph.  All my numbers used in arriving at that result were rounded off to only three digits, but the answer you get should be as accurate as your numbers for distance and time.

I think that lots of people have gone through this same process, and I would be really interested to know if anyone has seen this before.

[Trainman203]

I retired yesterday.  This is more work than I ever want to do again.😂😂😂

[edpb]

Trainman203, I sympathize.

[JLK2707]

Sorry to hear that mate!

[jward]

Since a scale mile in HO is approximately 60 feet, it follows that at 60 scale mph, a locomotive will take 5 seconds to run the length of a piece of flex track, and 1.25 seconds to run a length of straight, 18r or 22r sectional track. Using those figures and a stopwatch, you can extrapolate your locomotive's actual speed.


The nice thing about DCC (not EZ Command) is that you can reprogram the CVs to limit your top speed to whatever you prefer. The decoder will smooth out the rest of the speed curve.

[rich1998]

Some years ago I did that a few times with a three foot length of track on the layout before DCC and a stop watch. No big deal.

Rich

[JLK2707]

Have fun with that. Also, can you please show me some pictures of your trains?