Track pillars: 90064 (H-6) 3/16" ABS H-Column w/ 95412 (BM-6) 3/16" Base Mount on top. Total length about 3-1/2. Slide the bottom into a 90204 (ST-10) 5/16" ABS Square Tube which is cut 3/4". Total Height is 4". Each pillar is spaced 1-1/4".
Arms: 90084 (T-4) 1/8" ABS Tee cut 1" and placed at 45 degree angle.
Station Pillars: 90066 (H-10) 5/16" ABS H-Column w/ 95415 (BM-12) 3/8" or 95415 (BM-10) Base Mount on top. Total Length 2-9/32". You could use the base mounts on the bottom also. I had to cut them off as I am reusing old pillars from another layout that were taller. The base of the pillars here use 1/4 x 1/16 inch basswood. Each pillar is spaced 3-3/4".