G'day Alabama_Railfan,
..I would just like to add a little extra to the remarks made by RRSignal, who has the 'concept' he is endeavoring to impart correct but needs a little help with his 'math'...
...I will start by saying categorically (and without malice) that I abhor the American practice of using 'percentages' to designate the 'rake' of a gradient, which everywhere else in the world is achieved by using the more traditional terminology of
some distance "
in"
some other distance (for example 1 meter in 100 meters; 1 Foot in 100 Feet, et c.), ALWAYS with the first value being "1". This terminology can be IMMEDIATELY imagined, whereas, the 'concept' of percentages cannot. However, with some clever mental calculations (which can be difficult for those so "challenged"), a reference to grade as having 1%, can be envisaged if one takes the value provided (the 1%) and places this in the first part of the alternative statement and as these are percntage measurements ("out of 100"), one can then place the value 100 in the second place, thus giving a 'standard' 'rake' of 1 in 100. 1.5% would be 1.5 in 100 (which requires some further 'calculation', in the form of Fractional Arithmetic), to arrive at the gradient of 1 in 66; a grade of 2% translates as 2 in 100 or 1 in 50 and so forth...
..as RRSignal has indicated (albeit, improperly), this 'math' then translates on the ground as a rise of the first value after the 'passing' of the second value (in distance) along the entire length of the grade. To clarify this (using the '1 in 100' example), if the length of the grade were 100 units long, then the lower end (let's say it starts at a height of 0), would be 1 unit (and the actual units ARE irrelevant) below the height of the other end. If the length of the grade were double the original length (200 units), then the height at the high end would be 2 units higher and so on...
Jekrer {

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