Sweep1 surface not reaching end of rail

Hi there,

I am trying to sweep some triangles along curves I've created.  For some reason, the sweep is stopping before the end of the curve.

I've uploaded the files, but for clarity, I have created two surfaces. 

-  One: extra large, where I play with curves being modified by an attractor.

-  Two: smaller, which I use to clip the extra large curves

Thank you for the advice!

-  Jacob