For the legs (stands), I used aluminum (lowe's #215640) or steel 1" square bar, cutting two pieces 10-1/4" long. One end of each will have to be notched out by cutting out the three sides. The depth you cut depends on the width of your towers cross piece but for me it was 1-1/2". File everything smooth when done. Set the tower cross piece on top of the sides to mark and drill two holes for mounting (make sure the legs are 90 degrees to the towers cross piece). Allow enough seperation between holes for the nut on the backside. I used a 3" angled bracket mounted to each side at the bottom (the brackets will probably have to be much lower than the photo here shows - the track would lay on top of these brackets). You may have to make adjustments or reposition the brackets to fit your particular track. Drill a 1/4" hole (at a proper heigth) in each of the side post for the l-brackets. Also view this Photo. Note: (your dimensions will likely be different than the photo).
I used 1-1/2" x 1-1/2" x 1/16" aluminum angle (lowe's #55972) for the Towers Cross Bar 19 inches long (yours may vary because of the tracks width) This gives me plenty of room to mount the Status LED's. Find the center of your crosspiece and make a mark. Find the distance between the center of one lane and the center of the next lane on the track you will be using. Mine was 3-1/2". Then make a mark 1-3/4" in each direction from the center line on the cross piece. Now center and mark for all track lanes. At the same time you can mark the lines for the 'Lane Indicator' LED's which use the same center lines on the opposite side of the angle. See here. Drill a 7/16" hole (or ream a 3/8" hole) or for the overhead LED brass tubes. This allows for some fine adjustment space for the 3/8" all thread tubing. Drill a 1/4" hole for the LED lane Indicators. See here. Note: Save about a 3" piece of aluminum angle for use as a bracket when mounting the gate switch to the gate.
Two 5/16" holes will have to be drilled for the Status LED's. They can be centered somewhere between the side post and the end of the top cross piece. Four pieces of 1-1/2" all-thread tubing can be cut using a hack saw. Before cutting you should thread on a couple of nuts. When cutting always go with the direction of the threads, not 90 degrees. File and clean up both ends of the brass tubing. Attach the four pieces using two washers and nuts. Keep the Top of the tubing about a 1/16" above above the top nut.
You will also need a hole drilled at the Top of the Tower Leg for the Cable's exit. I found that a 3/8" hole and inserting a rubber grommet works fine. You may also notice a simulated track board in some of the photos. This is for shipping purposes and for testing of the hardware and sensors without having to have the track itself erected. You may also notice that I added a piece of angle for the back of the tower by using two small hinges. This allows for hiding of the wires and a cleaner finish. Using rivets or small screws works great for attaching the hinges.