In the late '70s. I caught a heavy manifest freight train out of Sparks, NV late one evening with 4 SD-45's on the point, and a 3 unit helper of SD-45's cut into the train. The engineer on the helper was the kind of engineer that did not help control the speed of the train very well. I knew this from experience. He would usually be either in full power pushing up, and full dynamic retarding going downhill. Not pleasant to have as a helper engineer. Coming west after crossing the bridge over Hwy. 80 approaching Colfax, there's a grade that is about 2 miles long. At this point, the engineer on the helper typically goes out of dynamic and goes into enough power to help push it up the small grade. This particular trip, we had a restricting track order not to exceed 20 mph starting at the depot at Colfax and proceeded west for about 1 mile. I started my slow-down procedure to enter the restricted track space but the train wasn't slowing down. I went into full dynamic and started applying the air and kept applying the air until I ended up with a 20-pound reduction before the train started to slow down. But, I went into the speed restriction at 30 mph, even with my attempts to slow down. About half-way in, I was still exceeding 20 mph, and guess what? We were being tested by several officials that were standing alongside the track. They called me on the radio and said, "Please stop your train." I told them that I would as soon as I possibly could. After stopping, the officials came up into my cab and asked me what the hell was going on! I told them the story, I had tried to slow down, and all I could think of was that the helper engineer must have fallen asleep in full power while he was pushing me up the grade. So, the powers-that-be went back and talked to the helper engineer. After they finished, they radioed me an OK to proceed west. Everything was fine until we approached Rocklin. I got a flashing yellow signal, and then a yellow signal, followed by a red signal coming into Rocklin. I stopped 20 feet from the red signal in full dynamic and full service with the train brakes and he almost pushed me past the red signal. About a week later, I was summoned into the office and received 45 demerits for going through the speed restriction for excessive speed. I know the helper engineer got some demerits too, but I never found out how many. It helps to have a helper engineer that helps you out with the train speed.