For Mark

[Mookie]

Only because you made a comment on knuckles that caused a question.

You mentioned Helpers (DPU's) which we see a lot of around here. When the entire train is going up and down hills the helper may not want to go uphill when the headend is going down.

My question is why would this happen and other than experience, how would an engineer know when to have the "help" and when not ot... that it isn't helping properly?

I figure part of the answer will be that the engineer knows his territory and the electronic equipment will give him a reading of what the whole train is doing, but is there more to it than that?

Little convoluted I know, but that is why Trains pays me the big bucks - to ask weird questions!

Mook

[Overmod]

I'll be looking forward to comment, but let me throw this in:

One of the points of DPU operation is to keep a point of neutral slack in the train, called the 'node', at all times. You call it 'distributed power' rather than 'helpers' to reinforce that understanding -- the point is NOT to have the extra engine(s) only shove on the train when 'needed', but to do active participation in moving the train at all times.

There is a certain amount of desirable sophistication in a DPU control scheme when you have long trains running over undulating profiles, because you may get several effective nodes instead of one, and you can't control (with existing equipment and sensors) the run-in if there isn't at least one DPU unit between each pair of such nodes.

I, too, would be interested in knowing what kinds of operational situations occur -- aside from dead engines -- that crop up as problems in DPU running.

[Mookie]

Right on! Now I have to ponder on it awhile to get it all aborbed!

Thanks, Mark!

Mookie