Steam & Excursion > Steam engines ever have main reservoir on the tender?

Someone had a pic looking down on the tender
of a PRR T1-- just behind the coal bin there
are two cylindrical tanks, maybe 2 ft diam
and 6 ft long. Not visible from ground level.
Were steam locomotives allowed to carry
the main air reservoirs on the tender?

Some narrow gauge engines on the Rio Grande had reservoirs on the tender.

I believe the NYC engines with the water scoops had reservoirs on the tender.

Out

callum_out Wrote:
-------------------------------------------------------
> I believe the NYC engines with the water scoops
> had reservoirs on the tender.

Some NYC fan I am. Until you mentioned that, I never noticed that the Niagaras have no visible air reservoirs. Didn't some modern engines have them mounted on the frame under the boiler? I don't think UP 844 shows any, either, nor the N&W J's. Maybe the cast frames had integral air tanks?

This photo of an NC&StL 4-8-4 cast engine bed seems to show an integral reservoir: http://www.nashvillesteam.org/wp-content/uploads/2016/05/576_Frame.jpg



Edited 3 time(s). Last edit at 01/17/17 20:10 by CPR_4000.

CPR_4000 Wrote:
-------------------------------------------------------
> callum_out Wrote:
> --------------------------------------------------
> -----
> > I believe the NYC engines with the water scoops
> > had reservoirs on the tender.
>
> Some NYC fan I am. Until you mentioned that, I
> never noticed that the Niagaras have no visible
> air reservoirs. Didn't some modern engines have
> them mounted on the frame under the boiler? I
> don't think UP 844 shows any, either, nor the N&W
> J's. Maybe the cast frames had integral air
> tanks?
>
> This photo of an NC&StL 4-8-4 cast engine bed
> seems to show an integral reservoir:
> http://www.nashvillesteam.org/wp-content/uploads/2
> 016/05/576_Frame.jpg

Cast integral frames usually did have the reservoir cast
into the frame, between the drivers.  Bosses were machined
and holes drilled and tapped for pipe connections.

The reservoirs on the NYC tenders might have been to operate
the coal pusher (when equipped) and or the lifting mechanism
for the water scoop (when equipped).
 

I've heard of auxiliary reservoirs being on a tender, and perhaps those reservoirs for operating the stoker apparatus or scoops, but not main reservoirs. How would you perform the required hammer and hydro test on a main reservoir which is cast into a locomotive frame?

EtoinShrdlu Wrote:
-------------------------------------------------------
> I've heard of auxiliary reservoirs being on a
> tender, and perhaps those reservoirs for operating
> the stoker apparatus or scoops, but not main
> reservoirs. How would you perform the required
> hammer and hydro test on a main reservoir which is
> cast into a locomotive frame?

You don't.

See part 230.72 (a).

As info, the walls on those things, being part of the main frame, are several inches thick.

The stoker is powered by steam.



Edited 1 time(s). Last edit at 01/17/17 23:24 by Realist.

>You don't.
>See part 230.72 (a).

OK, thanks. Never delved into the steam regs all that much.

NYC Niagara's reservoirs were built into the cast frames.

Ross Rowland's ex-C&O 614,  Lima-built 4-8-4, 1948, has a cast engine-bed frame with cast integral Main Reservoir..
Very robust, indeed.,.  All-around Timken rollers, aluminum cab, aluminum jacket sheets---- as close to a NYC Niagara as we'll ever see.  With 74" drivers, and a booster ---- she's a DIGGER, and a screamer.
Ross expanded tender coal capacity. Now holds virtually as much as a NYC PT-4 tender,  46 tons, no track pan scoop, though.
Dont ask about 614's booster.....

Re: the main res., I'm not sure about how to clean out decades of accumulated gunk; bu,t would be interested in hearing about ecologically-sound ideas.

W.



Edited 3 time(s). Last edit at 01/18/17 16:10 by wcamp1472.

wcamp1472 Wrote:
-------------------------------------------------------
> Ross Rowland's ex-C&O 614,  Lima-built 4-8-4,
> 1948, has a cast engine-bed frame with cast
> integral Main Reservoir..
> Very robust, indeed.,.  All-around Timken
> rollers, aluminum cab, aluminum jacket sheets----
> as close to a NYC Niagara as we'll ever see.
>  With 74" drivers, and a booster ---- she's a
> DIGGER, and a screamer.
> Ross expanded tender coal capacity. Now holds
> virtually as much as a NYC PT-4 tender,  46 tons,
> no track pan scoop, though.
> Dont ask about 614's booster.....
>
> Re: the main res., I'm not sure about how to clean
> out decades of accumulated gunk; bu,t would be
> interested in hearing about ecologically-sound
> ideas.
>
> W.

"Ecologically-sound"?  On a steam locomotive??

This isn't easy to do on account of cramped spaces,
but it is possible to take off one of the inlet pipes
and the drain plugs, and stick a 2,500-3,000 psi
pressure washer in there with a nozzle that will
hit a wide area.  You could catch what comes out
of the plug openings in a pan, I suppose.  It won't
be pretty.

The same device, with flexible wand and a variety of
nozzles, works wonders on the corners and crevices
when doing a boiler wash, too.

The reason for having an air tank on the tenders of late 19th century / early 20th century locomotives was for the same reason as there was (and still is) an air reservoir on each car.  That is, to apply to brakes on that car. The tender brake performed only in response to the engineers operation of the automatic brake valve.  Locomotive driver brakes, and leading truck brakes, were controlled by the independent brake valve only.  The independent and automatic systems were not integrated until the SW-A brake about mid1890's, followed by the more widely used A-1 brake of 1896.

-LD

This is a footnote to LarryDoyle's explanation ....

For clarity, George Westinghouse considered the braking capacity of the entire  train is a "unified system".

Thus, the "Main Reservoir" contains the "supply air'  for the train's brake air supply.   Each car's air supply ( for braking) is carried in the "Auxiliary Reservoir".  An obvious variant of MRs on a tender, are those mounted on the rear deck, behind the cistern,
of the tenders on some narrow gauge 2-8-0s, D&RGW locos...?

So, yes, there may be a tank on the tender, but there is a distinction between the functions of the two air reservoirs.

A variant is some locos built by the Reading RR patterned after clean-lined British-styled locos. The early British braking systems used a 'steam jet' to operate their vacuum brakes, and so, they had no air compressors " to hide".
The Reading wanted a clean-lined Pacific, a la British designs.

The Reading hid two, single-cylinder air compressors in the front water legs of the the tender, behind access doors.
That removed the air compressors from their loco mounting, and the clean lines of their engine are very striking appearance.
I am presuming that their main reservoir(s), likewise, are hidden in the tender.

So, like the old saying goes: " There's a prototype for everything!"

​W.


 



Edited 3 time(s). Last edit at 01/24/17 01:22 by wcamp1472.

Schedule A-1 dates to 1882, if not slightly earlier, and was automtaic air brakes only on the engine (and tender, provided the customer bought air brakes for the tender). An optional extra was a straight air valve called the "supplementary brake valve" for the locomotive brakes (source: 1882 WABCo pts catalogue). When this valve became incorporated as standard equipment with the A-1 system c1898, WABCo redesignated the system "SWA" (source: 1894 and 1900 pts catalogues). A-1 is named after the plate number (the illustration in the part catalogue), while SWA uses the newer mnemonic scheme "Straight With Automatic". Although SWA was superseded in 1905 by the E-T ("Engine-Tender") brake system, A-1 and SWA were still sold as new equipment at least as late as 1908-1910 if the customer specified them.

Tender brakes in the A-1/SWA era were the same as car brakes (IOW automatic air only, unless the purchaser specified the inclusion of straight air capability on the tender) with the exception that the triple valves were a slightly modified design specifically for use on tenders.

Aside from reputed details for the historical record, your comment is relevant to today's operational challenges, and today's curious students of steam, because....?

IMHO, this falls into the category of irrelevant trivia, "with no redeeming social value."

W.

>Aside from reputed details for the historical record, your comment is relevant to today's operational challenges, and today's curious students of steam, because....?

Because of accuracy and that I don't believe in braggadocio. There are a lot of readers who come here for the "straight dope", as we used to say on the SP, so my comments were to clarify another post which said SWA predated A-1 and to accredit why this is not so, without being so snide about it.

And this:

>Thus, the "Main Reservoir" contains the "supply air'  for the train's brake air supply.

is double talk, also with no social redeeming value (your phrase). The source of compressed air for a train's brake system is the air compressor on the engine. It compresses air, which is then stored in a (main) reservoir -- also on the engine. With an automatic air brake system, air flows from there to separate reservoirs, one on each car, which are "auxilliary" to the main one. The air stored in the auxiliaries is then used to apply the brakes on the cars. This is the way Geo Westinghouse described the system in his original patent.