A 1:20.3 locomotive is moving a lot slower in scale than even a 1:29 locomotive travelling at the same actual speed would be going in scale.... Matthew (OV)

To cover the same distance in the same time 1:20.3 scale is 7 MPH 1:29 scale is 10 MPH

The following can be used to calculate scale miles per hour for any scale and any timed length of travel. Best to use a stop watch to time the travel over a measured distance.

L = length of travel in inches F = scale factor T = time in seconds for locomotive to travel length.

Scale MPH = ((L x F/12)/5280) x 3600/T

Example: If it takes 5.2 seconds for a HO locomotive to travel over two straight pieces of Bachmann sectional E-Z Track. L = length of travel in inches: 18 inches F = scale factor: 87.1 T = time in seconds: 5.2

Scale MPH = ((18 x 87.1/12)/5280) x 3600/5.2 = 17.1 MPH

---------

To use Microsoft EXCEL Cell A1 enter length travel in inches Cell A2 enter scale factor Cell A3 enter time in seconds Cell A4 enter the scale MPH formula =((A1*A2/12)/5280)*3600/A3