This is a video of a logging truck going in empty, loading and coming out loaded. It shows how well a trailer tracks when loaded in the truck tracks but this fella is going slow enough that it doesn't track that well but you can see what we talk about. The operator on the shovel (loader) makes this look so easy but believe me, not everyone is as good as this fella. Todays trucks use electric scales so when the driver drags his lines up the reach to hook to the truck he also hooks up the scale line and then you get a read out in the cab. It goes between, TRUCK, TRAILER, and GROSS for both. It just flashes these numbers up. Then when getting near loaded, the driver CB's the operator and tells him the weights so they know where to put the most weight, ahead or to the rear. Very accuate system. In the old days, we used hydralic scales. Some ran brake fluid but we ran anti freeze, trying to keep and honest reading on the gauge and there was a gauge on the truck and one on the trailer so you had to run back and check the trailer gaugel often. Then we went to air scales which worked from the cab and now the electronic.
Anyhow, sit back and enjoy this video for a few minutes. Mike