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Doubleheading steam..

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Doubleheading steam..
Posted by Ulrich on Tuesday, November 9, 2021 7:54 PM

When doubleheading steam was it required that both locomotives be of the same type or approximate size? i.e. two Mikados or two Pacifics etc. 

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Posted by BaltACD on Tuesday, November 9, 2021 8:49 PM

Ulrich
When doubleheading steam was it required that both locomotives be of the same type or approximate size? i.e. two Mikados or two Pacifics etc.

Nope!  Whatever was available that would permit the train to conquer the grade.  In some locations, 0-6-0 and 0-8-0 yard power would be used - even in diesel days.

Never too old to have a happy childhood!

              

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Posted by Gramp on Tuesday, November 9, 2021 10:54 PM

How did the steam engine crews communicate with each other while the train was in motion?  (so they wouldn't operate at cross purposes).

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Posted by ATLANTIC CENTRAL on Tuesday, November 9, 2021 11:03 PM

Gramp

How did the steam engine crews communicate with each other while the train was in motion?  (so they wouldn't operate at cross purposes).

 

Whistles, brake air pressure guage readings, seat of their pants, experiance.

And steam and diesels often worked together during the transition era.

Sheldon

    

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Posted by blue streak 1 on Tuesday, November 9, 2021 11:04 PM

Vaguley recall reading about PRR Broadway that many 1st engineers would tell 2nd loco to pour on all the power possible and 1st would handle the slow sections.  A small brake pipe reduction to signal to 2nd to coast,??

Believe someone here posted all the aplicable whistle signals that were pertinent to multi engine operation of a train ?

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Posted by Paul Milenkovic on Thursday, November 11, 2021 11:22 AM

The Broadway was double headed with a pair of the same K4s type because the train had grown to where a single K4s would not maintain track speed, even on level portions of the route, and the Pennsylvania figured under their unique circumstances of making a large number of K4s of their electrification program.

An 0-6-0 or 0-8-0 locomotive would simply not do for this applications that was not about climbing a ruling grade at minimal speed.

Should we be answering a question that was asked in all seriousness with a dismissive "nope!", especially when the answer is more complicated than such a single-word answer?

If GM "killed the electric car", what am I doing standing next to an EV-1, a half a block from the WSOR tracks?

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Posted by Overmod on Thursday, November 11, 2021 11:59 AM

Ulrich
When doubleheading steam was it required that both locomotives be of the same type or approximate size?

No... nor was it required that only steam would be used -- there are plenty of examples of multiple-headed steam with diesel, and 'fully-working' diesel consists with steam.  We have discussed the physics involved, including the relative insensitivity to 'which locomotive does 'more' of the work, in past threads and posts here.

In practice the choice of engines would depend on factors like acceleration or expected sustained speed, ability to take water, whether a given grade required 'helping' or 'snapping', etc.

The case of PRR overkill is a bit more involved.  Until near the end of steam PRR remained enthusiastic about four-coupled high-speed power, so it would be howlingly logical to doublehead an E6s ahead of a K4s on any conceivable passenger or M&E consist that a single K4 could no longer accommodate.  In practice, however, the E6 was much too small to handle even abbreviated 'regular' PRR long-distance trains (especially with the rise of axle-powered AC and electrics) and as we know PRR had expensively committed to a large fleet of K4s just prior to the Depression... so with so much of the cost of doubleheading being in the engine crews, and the maintenance of a K4 being little more than that of an E6, it made sense for the overkill of putting the equivalent of a fairly large 4-6-6-4 on any train needing more than single K4 power.

The 'correct' answer was a workable 4-4-4-4... in the range of what Baldwin proposed, with around 102-104 GA and (eventually) independent control and trim of the engines.  Next best would be an R2 equivalent to the same '5/4 of an M1' that the Q1 science project tried to be... if given the lightweight rod technology and eight-valve poppers driven by B-2 bridged RC, these would handle any M&E plus passenger consist PRR could have fielded... and been readily snapped by any passenger power over any PRR grade...

... but would have come to the same early and lamentable end as 'the rest' of big PRR steam, in the same general time period.  That's another story.

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Posted by ATLANTIC CENTRAL on Thursday, November 11, 2021 12:05 PM

Paul Milenkovic

The Broadway was double headed with a pair of the same K4s type because the train had grown to where a single K4s would not maintain track speed, even on level portions of the route, and the Pennsylvania figured under their unique circumstances of making a large number of K4s of their electrification program.

An 0-6-0 or 0-8-0 locomotive would simply not do for this applications that was not about climbing a ruling grade at minimal speed.

Should we be answering a question that was asked in all seriousness with a dismissive "nope!", especially when the answer is more complicated than such a single-word answer?

 

Every railroad had different operating conditions, but the OP asked the question in a generic and open ended way. He got a reply based on that.

The B&O "generally" used Mikados as front end helpers on passenger trains pulled by Pacific's, and used diesels as helpers while leaving steam in place as the primary power.

The Western Maryland used RS units working with 2-8-0's to get loaded hoppers out of their mine branches.

Was matched power required? Nope.

Was it desired? Was it the operational procedure of some roads? Those are different questions.

Sheldon

    

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