How can I help my career with a broadening assignment?

First, you can't PCS again within a year.
While working at TRADOC isn't a broadening assignment, it is considered a more challenging assignment and is viewed more favorably than working as a SL in a BCT. You can submit for a broadening assignment at one year on station, but you are filling a demanding assignment already.

Look at DA Pam 600-25, it will tell you what the Army considers as the appropriate career progression for assignments, positions, schools, ASI and SQI by MOS, by Grade. Also go on line and pull up the board AAR results for the most recent SFC board it will list what was generally considered favorable or less- favorable for broadening assignments and duty positions and the length of time considered as fully qualified for serving in those positions.

I see that you are an Engineer, contact the SGM at the Engineer Personnel Development Office (EPDO) here at Leonard Wood [login to see] then EXT 3-6137. They can tell you what positions are priority fills or shortages. Then call HRC and ask about filling one of those positions. You're not going anywhere for at least a year as the Army won't PCS you twice in the same year.

As an Engineer 12B, SSG serving in a Squad Leader Position, you are rite where you should be regardless if you served as SL previously as a SGT. That's where looking at the board AAR comments come in, to see how long you need to remain an SL to be competitive. Drill Sergeant and Recruiter have consistently been considered as favorable broadening assignments for Engineers by the boards.

Hope this helps.

Branch is correct, you won’t be able to move if you’re less than 12 months on station. Also you have to keep in mind unless you get selected for SFC, Recruiter or Drill Sergeant, you’ll be on station for 36 months. While assigned in your current position there are additional duties you can attend training for to help with your career (EOL, Victim Advocate/SHARP and MRT. Good luck to you....