How do you grade your garden railroad?
Based upon modeling resources for all different scales the maximum gradient should not exceed 3%. Irrespective of scale, Of course, this greatly depends on the weight of the locomotive, drive mechanism, number of locomotives (MU‘s) and the number of cars or carriages (consist). Even with the prototype, 12” to 1 foot scale, difficulties can be experienced on a gradient incline in excess of 2%.(1:50)
At the Vines Garden Railroad the terrain on either side of the ravine gave rise (No pun intended) to gradients in excess of 5%. This, together with an average 5 foot radius curve, can provide severe restrictions even with the heaviest of locomotives and the smallest consists. One of our best performers is the ACL F-3A and B however this is powered with four motor driven trucks geared to eight axles.
Percentage gradient measurement can be of any linear dimension. Inches, feet or miles.
For example: 1% being a 1” rise (or drop) in 100” of length.
One relatively simple method of measuring the actual grade can be undertaken by the use of a carpenters four foot level and three pieces of scrap wood. Although it is possible to provide a rough gradient figure of 1% by using 0.5” over 48”. For our purpose we used centimeters or one centimeter in one meter.
The carpenters level is measured and marked at one meter (39.37”) along its length.
To find a common base with respect to the track (rail height) two blocks of wood are cut to traverse the track. These will be placed under the carpenters level, 100 centimeters apart, at the marks placed on the level.
One more piece of wood is cut with one centimeter steps and marked as 1, 2, 3 and 4%. The width of each step corresponds to the width of the carpenters level.
To find the actual percentage gradient place the carpenters level on the step where the bubble shows level.
It is realized the gradient as measured over a curve is not going to be accurate but - as the saying goes. Close enough for government work!
This method is being used at the Vines Garden Railroad with good success as we have now been able to re-grade certain parts of the track to a maximum of 4%. We can now navigate most grades with our single locomotives and eight or ten car consists. We would like to bring all gradients down to the 2% level but this would require much cutting, to lower, and elevating above ground level. Not a very practical consideration on this particular layout.
Norman Allum - 6/08/09
JSE Designs, LLC