Rookie Railfan Questions

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Posted by CShaveRR on Wednesday, September 11, 2019 11:36 AM

I'll let one of our engineers answer in more detail, but all locomotives use the same 27-pin jumper cable for m.u.ing.  It doesn't matter who built them, they will work together, to some degree.

Carl

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Posted by tree68 on Wednesday, September 11, 2019 1:45 PM

CShaveRR
I'll let one of our engineers answer in more detail, but all locomotives use the same 27-pin jumper cable for m.u.ing.  It doesn't matter who built them, they will work together, to some degree.

All of our locomotives (all vintage) will run together, although I'm not sure what the arrangement is for the RS-3 with manual transition.  We've got EMD's and ALCOs.

LarryWhistling
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Posted by CSSHEGEWISCH on Wednesday, September 11, 2019 1:57 PM

You're lucky you don't have any vintage Baldwins with air throttles and related MU system.  They won't MU with anything except their own kind.

The daily commute is part of everyday life but I get two rides a day out of it. Paul
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Posted by BaltACD on Wednesday, September 11, 2019 2:42 PM

CSSHEGEWISCH
You're lucky you don't have any vintage Baldwins with air throttles and related MU system.  They won't MU with anything except their own kind.

Their own kind are communing with the dinosaurs.

I think I recall one carrier that revised the Baldwin control system so that their Baldwin's could be MU'd with the carriers other power - I may be mistaken.

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Posted by Overmod on Wednesday, September 11, 2019 3:39 PM

BaltACD
I think I recall one carrier that revised the Baldwin control system so that their Baldwin's could be MU'd with the carriers other power - I may be mistaken.

You'd be correct.  I believe Baldwin would also build you a locomotive compatible with eight-notch electric MU if you wanted.

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Posted by Flintlock76 on Wednesday, September 11, 2019 3:45 PM

Overmod

 

 
BaltACD
I think I recall one carrier that revised the Baldwin control system so that their Baldwin's could be MU'd with the carriers other power - I may be mistaken.

 

You'd be correct.  I believe Baldwin would also build you a locomotive compatible with eight-notch electric MU if you wanted.

 

Quite true.  There's photos of Erie Baldwins MU'd with ALCOs and EMD's.

And if I remember correctly, Baldwin sold a MU adaptor kit as well, just in case you found out you needed one after all.

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Posted by Overmod on Wednesday, September 11, 2019 3:59 PM

steve-in-kville
if two locomotives are at the head of a train, one is an EMD and the other a GE, must they be "calibrated" to work together? Due to the different make/model, won't one pull harder? Are the throttle notches universal?

There is more to this: different locomotives do pull differently, and in some cases, for example if they have very different traction-motor gearing, they develop very different TE at a particular speed.  This is only "important" when running them together in that both the low-speed instantaneous and hourly equivalents and the permissible 'top speed' will be limited to what the 'least capable' of any unit in the consist can exert.  It may seem unusual that, say, a switcher and a large road unit can be MUed together, but each will be exerting its proportional TE at a given commanded notch.  The train will accelerate to a 'balancing' speed determined by available power against train resistance, and the speed will then vary up and down with 'terrain' and environment if the engineer doesn't adjust it by going to a different notch or using the brake.  Notches control output power, not road speed directly.

A more significant distinction is difference in loading speed -- the locomotive equivalent of acceleration.  Some GEs in particular are painfully slow to speed up the diesel engine and apply electrical load to it, and what you then see is a relative pulling or bumping of units in the consist (Trains has commented at least once on the phenomenon) as the fast-loading units develop more TE than the slower.

While we are on the subject of GEs, some of them went to a 15-notch throttle (giving finer gradation when running, closer to what a Baldwin could do with its stepless proportional air throttle).  When running in MU, only the nearest 8-notch equivalent would be sent, and if running in trail only the 'corresponding' eight notches would be recognized.

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Posted by tree68 on Wednesday, September 11, 2019 8:14 PM

Overmod
A more significant distinction is difference in loading speed -- the locomotive equivalent of acceleration.  Some GEs in particular are painfully slow to speed up the diesel engine and apply electrical load to it, and what you then see is a relative pulling or bumping of units in the consist

Even the brand of governor can make a difference.  Our two RS18u's have different governors - one GE, one Woodward.  I can never remember which unit has which brand, but I do know that when I notch up one, it's a nice, smooth increase in RPMs.  The other, however, responds to an increase in the throttle with a "snort" and it's off to the races...

LarryWhistling
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Posted by Lithonia Operator on Wednesday, September 11, 2019 8:32 PM

steve-in-kville
I'm trying to wrap my head around the term "stringlining." Is when the train isn't kept tight and the car's couplers start rattle? I've heard the term "jack knifing" as well. Please explain.
 

It's when a train is underway on a curve, and some of the train tries to take the "direct route." That is, it tries to cut off part of the curve. It takes what sailors would call the rhumb line, the shortest distance between two points.

Imagine if you picked a spot on the track and attached one end of a string to that point. Then further along the curve, you pulled the string tight, then attached the other end. The string will not follow the track; it will cut staight across the ground on the inside of the curve.

Now imagine if a part of train tries to go this route. This can happen if there is a group of light cars located between two sets of heavy cars. Those light cars try to take the "string line." And of course they derail.

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Posted by tree68 on Wednesday, September 11, 2019 8:35 PM

Lithonia Operator
Imagine if you picked a spot on the track and attached one end of a string to that point. Then further along the curve, you pulled the string tight, then attached the other end. The string will not follow the track; it will cut staight across the ground on the inside of the curve.

Just lay a length of string out on a table in an arc, then pull on the ends.

If you're a model railroader, put a train on a curve and pull on two end cars.

LarryWhistling
Resident Microferroequinologist (at least at my house) 
Everyone goes home; Safety begins with you
My Opinion. Standard Disclaimers Apply. No Expiration Date
Come ride the rails with me!
There's one thing about humility - the moment you think you've got it, you've lost it...

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