Richard, while technically, you can use the word flange for a ridge for strength or attaching point, I found it confusing when applied to the foot of the rail, in fact your wikepedia article shows flange as most people would expect, on the edge of a wheel.
Using a “wide open” interpretation, you could probably try to call the rail head itself a flange (it’s wider for strength, which “satisfies” the general definition in wikipedia).
Like I said, flanges in railroads are usually on wheels, or steam pipe fittings, and the rail already has VERY specific terminology, head, web, foot, etc. that makes things CLEARER. I was just indicating that on a small screen the pictures shown, I could not see a flange as I would expect it.
Greg