Some consists are very hard to handle. I have had modern AC traction units mixed with General Motors GP9 locomotives of the 1950s. In high power, but low speed situations, the older unit is more likely to slip its wheels, because the traction control system is so crude compared to the modern ones. You have to know the engines that you are working on. Some do load faster. GE units through the -9/AC4400 classes were slow. The engineer has to throttle up earlier approaching hills, as it takes them longer to reach full power. The new Evolution Series GE models load fast, as to the GM units. Sometimes the fast loading units are at full power, while the slower one is still catching up. Yesterday I was on a train which was a good example. I had a GE ES4400 leading an AC4400. Luckily the ES was leading. It would already be at full power, while the other was still thinking about it.
I sometimes run trains with remote units in the train. They can be controlled to match what the lead consist does, or controlled separately. They sometimes need to be separated due to the terrain. My experience of the power, and the terrain help me judge what to do. The experience of having run similar trains over the track several hundred times helps too. I know how to use downhills to my advantage, so I get more run at the ups. An engineer who is new might misjudge, and be stuck struggling along until he gets a new down to help him out.
I sometimes run trains with remote units in the train. They can be controlled to match what the lead consist does, or controlled separately. They sometimes need to be separated due to the terrain. My experience of the power, and the terrain help me judge what to do. The experience of having run similar trains over the track several hundred times helps too. I know how to use downhills to my advantage, so I get more run at the ups. An engineer who is new might misjudge, and be stuck struggling along until he gets a new down to help him out.
