Dan Padova posted:I can almost understand, though not fully, how one manufacturers different locos can work.
However, with the combination I mentioned in my first paragraph, how do the units coordinate as far as speed and pulling power ?
Dan, there are eight throttle positions. When the throttle of the controlling locomotive of a consist is in, say, Run-5, then each locomotive of that consist does what it is programmed to do any time it is in Run-5, regardless of where it is in the consist, or what other locomotives are in the consist.
Therefore, in a consist of EMD F7's and Alco-GE FA2's which are sitting at idle, when the Engineer places the throttle in Run-1, the F7's begin a slow process of amperage buildup, while the FA2's immediately produce about 200 amps of traction power, because that is what they are respectively designed to do. As speed increases, the Alcos will make transition at pre-programmed speeds measured by an axle generator, while the EMD's will make transition based on the amount of amperage being used by the traction motors. Each does what it was designed to do when given the same throttle command.
