+Tile Factor:
Defines the beam texture tiling factor. Second number defines the tiling type. Type 0 tiles the graphic in the beam as many times as defined by the 1st number. Type 1 uses the 1st value as the lenght[sic] of the tile.
Syntax: Float, Integer
So... Type 0 with 1 tile from source to target, and an [animated] image that looks like it comes from a point and fans out (like those thruster thingies)?
[EDIT] This would scale with distance and might look weird in some situations, like if two tractor beams are targeting two ships at very different distances. Probably would still work though