Same thing - achieves same purpose. Many guard rails also use only the compound filed end without a bend. You want a 'gather' that is less the 10 degrees of angle - otherwise you run the risk of a bumping and possible derailment rather than the function actually guiding the flanges in place.
-ed-
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-ed mccamey-
COSLAR RR -
http://www.coslar.us/NMRA Standards and Conformance Department
PROTO & FINE Scale Coordinator
I estimate I have about 5 pounds of coupler springs somewhere in the vicinity of my workbench.