Gmod Wire SVN logic question

Hey guys, I was just wondering if anyone would be able to help me out with a testing rig that I am setting up for my physics class, what I have is a roller coaster on a straight track, and is suspended by hover-balls, and is pushed by some thrusters, so far so good, but when I try to set up a wire circuit thingy that will start a timer when a ranger is crossed, and then stop it when a second is crossed, I just can’t get it to work. I tried using a d-latch ram, and some and gates, basically saying that if ranger >= 0 then clck = 0, and the data would be from the ranger >=0 gate. I tried using that but I can’t seem to get it to work. I also googled my predicament for possible solutions, but to no avail. If you guys know of a solution, it would be great if you could inform me of it. Because I am using this for a class assignment, it would be great to have it answered by the 3rd of October. Thanks for your time and help!