Thus if cell name = US6whatever write it to the 6 shapefile, US5whatever write it to the 5, etc.

You can just create a fanout attribute using the @Substring expression

Thanks! Though I don't quite have the Attribute Value correct. So Value gets the CELL ?

If the attribute containing the string is called CELL then you want

@Substring(@Value(CELL),2,1)

 @Value(CELL) is the string to use

2 is the start index (index starts at 0 so this is the third character)

1 is the number of characters to keep from that point

Still no go. AttributeCreator (AttrSetFactory): An error occurred while evaluating the above expression. If the failed expression is arithmetic, check to ensure there is a numeric value specified as the substitution value for null, empty and missing attributes.

AttributeCreator (AttrSetFactory): AttributeCreator: Failed to evaluate input expression: @Substring(@Value(CELL),6,5,4,3,2,1)

Does it need to know it's splitting on the 3rd character?

I've added some explanation to my above post, you should enter it exactly as i posted

Writing, but still not splitting, creates 6 duplicate shapes.

Once you've got an attribute to Fanout on, you use this as the Shapefile Name within the writer. You only need one writer.

That's it! thank you very much!!