1. The "engine suddenly shut down" is a random feature or scripted for 0Z02 service? 2. What exactly happen at 34 MPH and do I need to reduce the throttle after reaching this speed?
1. Engine shutdowns are not supposed to happen in service mode. It's a bug. 2. I don't think you need to reduce throttle.
It's the field divert (called transitioning in the US) kicking in. I wouldn't reduce the throttle. In fact if the amps reduction loses you speed (e.g. if you're on a uphill gradient) you might want to add some. But most of the time just leave the loco to sort itself out.
Not quite a field divert, field diverts are *slightly* different to what this is but has a similar effect, it is a transition in this case. In this case its the generator field windings I think going from series to parallel (or it may be the other way around), the generator quickly unloads to allow the transition to occur before loading again. A field divert is done on the traction motor, they effectively are a resistor shunt across the motors field, which has the effect of diverting current away from the motors fields weakening them. This has the effect of causing the current to jump suddenly as the divert kicks in. This is most noticeable on British diesel locomotives and there are typically 3-7 of them.
