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ATSF Steam Switcher Valve Gear Question

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  • Member since
    January 2017
  • From: Southern Florida Gulf Coast
  • 18,255 posts
ATSF Steam Switcher Valve Gear Question
Posted by SeeYou190 on Friday, August 11, 2023 12:00 PM

This beauty showed up on Brass Trains Dot Com:

This model does not have a valve gear. Given the level of the rest of the detail I find it hard to believe that this prominent detail was ignored by the builder.

Did ATSF steam switchers have hidden or simplified valve gear?

Or, was this a blatant omission of parts? I do not see anywhere on the main driver for the valve gear eccentric to connect.

Thanks.

-Kevin

Living the dream.

  • Member since
    February 2008
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Posted by AEP528 on Friday, August 11, 2023 12:14 PM

Looks like an accurate model of Santa Fe 9005, which was renumbered from the 2000/2100 series. I don't know what type of valve gear that is, but it appears to be internal. Note that the power reverse is connected to something behind the drivers.

Edit: Possibly Stephenson inside valve gear?

  • Member since
    January 2017
  • From: Southern Florida Gulf Coast
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Posted by SeeYou190 on Friday, August 11, 2023 1:05 PM

AEP528
Looks like an accurate model of Santa Fe 9005, which was renumbered from the 2000/2100 series. I don't know what type of valve gear that is, but it appears to be internal.

It sure does. Thank you for that link. This locomotive does not seem to have many of the features that scream out "SANTA FE!" to me.

It looks like it might be similar enough to my other small brass steamer that they could pass for family.

-Photograph by Kevin Parson

Or, am I missing something that makes it look like these two could not look at home togther on the same roster?

-Kevin

Living the dream.

  • Member since
    May 2019
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Posted by BEAUSABRE on Friday, August 11, 2023 1:25 PM

It's called Stephenson Valve Gear

"American locomotives universally employed inside Stephenson valve gear placed between the frames until around 1900 when it quickly gave way to outside Walschaerts motion. In Europe, Stephenson gear could be placed either outside the driving wheels and driven by either eccentrics or return cranks or else between the frames driven from the axle through eccentrics, as was mostly the case in Great Britain."

Stephenson valve gear - Wikipedia

Here is a PRR Class H6sa Consolidation as seen in 1933. 1041 were built 1901-1905 as H6a (wide firebox) and it was one of a number converted to H6sa (superheated) in the Twenties. As was stated above, Stepenson Gear was "business as usual" at the Turn of the 20th Century. The piston valves were probably applied replacing D valves when it was superheated. 

 

 

 

  • Member since
    January 2017
  • From: Southern Florida Gulf Coast
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Posted by SeeYou190 on Friday, August 11, 2023 3:36 PM

BEAUSABRE
As was stated above, Stepenson Gear was "business as usual" at the Turn of the 20th Century.

Continuing down a rabbit hole...

Could I build my Bowser "docksider" 0-4-0 without the optional valve gear kit (which I have yet to purchase) and just claim it has a Stephenson valve gear? Is that plausible?

-Kevin

Living the dream.

  • Member since
    January 2013
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Posted by PM Railfan on Friday, August 11, 2023 5:40 PM

Kevin)

It does seem a lil naked without the valve gear doesnt it? 

Leaning modern cylinders or square tops were a dead giveaway for Stephenson inside valve gear workings. Hard to believe they were one this much of a modern loco. 

As you can see, the PM's were pretty simple in the valve gear department too. Though, one very hard thing to find in HO scale.... 

An 0-6-0 switcher with the main crank on middle driver! Especially in PM flavor. MDC 0-6-0's usually get the closest nod.

I can atleast match the tenders....

 

Did you get the 0-6-0?

 

 

Douglas

 

 

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Posted by BEAUSABRE on Saturday, August 12, 2023 12:21 AM

SeeYou190
Could I build my Bowser "docksider" 0-4-0 without the optional valve gear kit (which I have yet to purchase) and just claim it has a Stephenson valve gear? Is that plausible?

Well, I won't report you to the prototype police (grin).

Remember that the C-16's were anything but typical, being modern - outside valve gear, piston valves, superheated, all they lacked was power reverse - giants among their type as the 0-4-0 was pretty passe after 1900 and they were built in 1912. Their only competion was the PRR's A5s, built in 1916-1924 for essentially the same type of service. The B&O refurbished them and tried to sell them, but there were no takers. THey were too big and heavy for almost all short lines. Why such an atypical prototype? Because available model motors of the time needed all that space under the boiler and saddle tanks. 

Having said, there were lots of railroads who wanted the cheapest switchers possible and would have nixed superheating, piston valves, etc. Here is a PRR Class A4 (1906-1913) which shows that type of locomotive - D valves (ie no superheater), Stephenson Valve Gear, etc).

 

So it's possible, just not likely, IMHO.

Not sure how well a HO 0-4-0T would run. Four wheels for electrical pickup isn't much and it may stall on turnouts and crossings. You may want to try installing rail wipers as well. 

  • Member since
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  • From: Southern Florida Gulf Coast
  • 18,255 posts
Posted by SeeYou190 on Saturday, August 12, 2023 8:59 AM

PM Railfan
It does seem a lil naked without the valve gear doesnt it? 

It does. The lack of the valve gear stuck out very prominently when I looked at the model.

PM Railfan
Did you get the 0-6-0?

Yes, but not the one from Brass Trains Dot Com. There was also one for sale on eBay yesterday. I grabbed the eBay model.

The pilot is not bent, it has never been installed. There is supposedly a provision to remove the scale coupler box and install a Kadee front coupler.

BEAUSABRE
Well, I won't report you to the prototype police (grin).

Thank goodness. Honestly, if the prototype police have a "ten most wanted" list, I am probably on that already.

BEAUSABRE
So it's possible, just not likely, IMHO.

Plausible is all I am going for. Thank you for all of the useful information you shared. I truly appreciate that.

BEAUSABRE
Not sure how well a HO 0-4-0T would run. Four wheels for electrical pickup isn't much and it may stall on turnouts and crossings. You may want to try installing rail wipers as well. 

I doubt I will ever build the 0-4-0T kit. I have built the Hobbyline plastic 0-4-0 tank locomotive model, and I use it for photo-prop duty.

-Photograph by Kevin Parson

It still needs more detail and paint, but I really don't need a running 0-4-0 tank engine. I have a whole fleet of inoperable props for photographs.

-Kevin

Living the dream.

  • Member since
    September 2003
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Posted by Overmod on Saturday, August 12, 2023 6:01 PM

"Stephenson" is a link gear, mounted between the frames, typically driven by four eccentrics on one of the driver axles.  Circumferential straps riding on the rims of the eccentrics stand in for the cranks used for valve motion in an outside radial gear like Walschaerts.

On most evolved 4-4-0 and similar locomotives, the valve chests for the slide valves were outboard and horizontal, above the cylinders.  The link motion of the Stephenson gear was then translated by a simple bell crank and reach-rod arrangement so the motion was correct along the axis of the piston rods.  To me this is clearly on Kevin's model (the piston rod is bright silver; the crank is partly hidden behind the transverse hanger and may be a brass casting...)

This method worked niftily for piston valves, when those were introduced, and you might see 'Universal" chests with piston valves and appropriate ports that bolted on over existing cylinders to convert them.  On the other hand, with the easier maintenance necessary on piston valves, many early engines tilted the steam chests so the piston-valve stems lined up fully with inside motion -- it's relatively easy to find examples from the early 1900s as piston valves became desirable with the advent of superheat.  Some locomotives so equipped had an almost cockeyed look.  I believe most of the locomotives equipped with Vauclain type 1 compounding (the type with the smaller HP cylinder directly over or in a few cases under the LP) used inside drive to the complex type of piston valve used for those engines.

Most of the engines with the bell-crank drive to outside valves could be modeled very simply, as all the actual valve-gear motion was inside, including the connections to reverse.  All that would be needed would be some arrangement to walk the bell-crank shaft forward and back in 'time', and then arrange the bell cranks relative to engine quarter, then pin the ends of the cranks to linkage that drives the 'piston rods' in the chests.  A great many people here who don't care about fully scale operating appearance a la rotating bearing end caps will be happy just duplicating the crank arrangement and linkage components with a little sheet and wire...

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