"autorack rule " on NS east slope Pgh division

[rhotond]

Several times not I have heard NS pgh division crews refer to "the autorack rule" on the pgh division east slope (horseshoe curve).  This appears to have been implemented after the second derailment at the new Altoona interlocking coming down the hill.  The interlocking is on a vertical curve and this may have something to do with it.

Viewing trains over the last month does not seem to indicate any special placement of autoracks (loaded or empty) in the trains. 

Thanks for any info on this "rule" 

rhoton