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Eastern Railroad Discussion > Helper question


Date: 08/12/19 12:35
Helper question
Author: Cumberland

When helpers are added, how does its engineer determine the speed at which its locomotive should be set to move, without crushing the string of cars, but effectively lowering the amount of resistance the lead consist has to fight?

I can imagine this question could have a lot of answers, applying to different scenarios. I'm mainly thinking in terms of when helpers are added on a grade.

Matthew



Date: 08/12/19 12:45
Re: Helper question
Author: engineerinvirginia

It's partly a matter of experience, but the head end will say how much power is needed if he feels the pusher might not be sure. Likewise when the head end starts to go over a hill the rear has to keep pushing, but at some point will ease off and begin to enter dynamic braking....the head end will tell the pusher when braking assistance is actually needed, but the pusher will be off power and ready to respond as soon as that request is made. It's all fits in with being qualified on your road...you know more or less where the head end is, and what the tonnage is doing....so when the head end prompts for something you are probably already there or close to it. The newer you are as a pusher engineer the more prompting you will get from the head end, and nervous nellies will prompt even a seasoned pusher.....it's all in a day's work.  



Date: 08/12/19 16:58
Re: Helper question
Author: callum_out

Old SP, helper in run 8, head end determines speed, as to crushing cars, there were timetable limits on
the amount of hp/tractive effort allowed if behind a caboose. There was much care in where there helpers
were placed in the train to balance the pushing and pulling of the helper set. Four or five units could be
used if carefully cut into the tonnage.

Out



Edited 1 time(s). Last edit at 08/12/19 17:01 by callum_out.



Date: 08/13/19 09:16
Re: Helper question
Author: ExSPCondr

callum_out Wrote:
-------------------------------------------------------
> Old SP, helper in run 8, head end determines
> speed, as to crushing cars, there were timetable
> limits on
> the amount of hp/tractive effort allowed if behind
> a caboose. There was much care in where there
> helpers
> were placed in the train to balance the pushing
> and pulling of the helper set. Four or five units
> could be
> used if carefully cut into the tonnage.
>
The above statement is correct, here's how it was done:

1.  Add the horsepower of the road engine and the helper engine to get total horsepower.
2.  Divide the total horsepower by the tonnage which gives horsepower per ton.
3.  Divide the tonnage by the road engine HPT, which gives the tonnage the road engine will handle.
4.  Divide the tonnage by the helper engine HPT, which gives the TOTAL tonnage the helper engine will handle.
5.  Divide the tonnage handled in #4 by 3, as the helper was supposed to shove 1/3 and pull 2/3 of its tonnage rating.
6.  Cut the helper in at that point, which could be moved several cars in either direction if restricted cars were encountered.

Operations over Donner also had to contend with the 5000 Ton drawbar limit Eastbound, and 6000 Ton Westbound if I remember correctly, which meant that the roundhouse foremen had to put mostly SD40s on the point, and SD45s in the helper, or the road engine would try to handle too much of the tonnage, and exceed the front drawbar rating.
G



Date: 08/13/19 10:16
Re: Helper question
Author: timz

> When helpers are added, how does its engineer
> determine the speed at which its locomotive should
> be set to move

He doesn't determine its speed -- the road
engineer does that. The helper engineer
watches the train's speed and knows when
he needs to shove, knowing where the
train is. If they're making 15 mph on a
steady upgrade, he knows he can leave
the throttle in Run 8.



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