New York Central variants question

Typically, New York Central Hudsons have, just in front of the main smokestack, a smaller, auxiliary, stack: it's for exhaust steam from the booster engine. (The aerodynamics of the inside of a steam locomotive smokebox are complicated, and -- certainly at the time the Hudson's were built -- poorly understood. You want the upward air current entailed by the steam from the best pipe to be strong enough to keep a good fire going, but not so powerful as to lift coal and blow it out the stack. I assume that having a separate pathway for steam from the booster engine simplified the problem.)
The prototype, 5200, did not have this auxiliary stack, and neither, apparently, did the first production batch (the J1b class). Later Hudsons, including at least the Lima-build J2, did have it. The New York Central locomotive diagrams reproduced in Alvin Stauffer's "Thoroughbreds" include a single diagram labeled as applying to J1c, J1d and J1e: it shows the extra stack.
QUESTION 1: was this design feature in fact introduced with the beginning of the J1c production run?
Fairly late photos of 5200 and J1b engines (in Stauffer) show them without the auxiliary stack, but
QUESTION 2: were any of the Hudsons initially built without this stack retrofitted with it on later rebuilding?
(I plan to crosspost this to the "Steam Locomotives" board.)
(I have cross-posted this to the "New York Central" forum.)

I had a look through “Loco Profile 2: New Your Central Hudsons”, by Brian Reed, for any insights on this item. This may have been a less well-circulated work on the subject than say Staufer, and perhaps some non-negligible distance further along the “scholarly” vector. Reed – who had apparently worked for North British during the steam era - was certainly very knowledgeable and had the industry contacts. He could also be acerbic and had strong views on some matters. But he was also visionary, and apparently saw the diesel future back in the 1930s. He was allegedly responsible for getting the “Railway Gazette” journal to start its “Diesel Railway Traction” series as a spin-off item. Thus, he was able to provide good engineering commentary on steam locomotive technology, uncoloured with commentary about how that technology was unjustly brought to a premature end, and I think without multiple use of the adjective “magnificent”.

Anyway, from the Loco Profile, the prototype was booster-fitted, but from the builder’s photograph, did not have the booster exhaust stack ahead of the main stack. Just where the booster exhaust was located was unclear.

Next, it was said of the B&A J-2b fleet:

“B. & A. locomotives could be distinguished by large rectangular sandboxes above the boiler, which were fitted shortly after the engines went into service. They also had a small stack, taking the booster exhaust, in front of the main stack, a fitting that was used nearly a decade later on some of the N.Y.C. class J-3a engines. All had Coffin feedwater heaters.”

Then, discussing the J-1 fleet as a whole:

“All engines under J-1a to J-1e classification had the same starting tractive effort at 85 per cent of 42,250 lb. from the main cylinders and 53,150 lb. with the booster in operation”

Thus. it looks as if all were booster-equipped.

In respect of the J-3a, it was said that the booster exhaust had a passage of some 55 ft. before it reached the auxiliary stack at the forward end of the smokebox top.

Then a discussion on the various exhaust nozzle arrangements used on the J series included this:

“J-1e nozzles were crossed in primitive fashion by ½-in. diameter bars; and booster exhaust was through a surrounding ring of 32 holes of ⅝ in. diameter, thus differing from the J-2 engines.. The blower was simple in the extreme, comprising two ⅜-in. diameter pipes projecting upwards about 2 in. at an angle of 5 deg. from the vertical. This construction replaced the normal ring blower when the space occupied by that fitting was needed for the annular exhaust of the booster. In some of the J-3 engines reversion was made to the J-2 arrangement of a ring blower, and a separate exhaust stack for the booster just in front of the main stack, but in other engines, to save a little weight, booster exhaust was taken to the tender.”


Cheers,

By way of an addendum:

The Loco Profile series of publications do not seem to have yet made it to the internet in .pdf form, at least at the usual sites. But they do seem to be available second-hand, e.g. from Amazon, at not unreasonable prices, at least in the north. (Today’s freight costs make virtually any SH books from northern sources non-starters in the south.)

As well as #2, the following would appear to be pertinent to some of your recent posts:

Loco Profile 20 – The American 4-8-4

Loco Profile 24 – Pennsylvania Duplexii


The latter certainly shows the acerbic side of Brian Reed!


Cheers,

Dear Pneudyne--
I have copies of the three "Loco Profiles" fascicles you mention (acquired long ago, in the Northern Hemisphere), but stupidly didn't reread the Hudson one before posting. (As for the Pennsylvania Duplexii, there is a lot to elicit acerbicness there--maybe more about the thinking of the railroad's top management than about the actual engineering!)
I'm puzzled about the description of the J2's arrangement. A ring of small(-ish) openings sounds like something to put in the smokebox itself (around the primary blastpipe?), but if they had this arrangement for booster exhaust, why would there ALSO be an auxiliary smokestack?
It also sounds as if there was a fair bit of modification to at least some J-class locomotives after their construction. (We already knew that in other areas: the distribution of Elesco vs Worthington feed water heaters lat in the locomotives' careers certainly suggests a policy of "install Worthington at rebuilding, unless the shop is too busy, in which case don't bother."
As to the J1 subclasses... I don't think they were all built like the prototype: there are too many photos of later J1 that show the auxiliary stack. (And, given that the bikers of the J1 and J2 were virtually the same otherwise, why would they have continued with the original arrangement for later J1 after specifying a different arrangement for the J2?)
As to the J3... I don't think I have seen an photos of NONSTREAMLINED J3 without the auxiliary stack, but its presence or absence is hidden in the streamlined locomotives... which were probably the ones where weight savings would be most desired.
So... THANK YOU! (And I now feel if anything MORE puzzled about the matter.)

It is certainly not easy to deduce why NYC made these variations.

I think it is reasonable to assume that a ring blower was more efficient, although not necessarily more effective than the simple pipe type, so was likely the preferred implementation where not otherwise precluded, such as where the ring was required for the booster exhaust. (Presumably dimensional limits outruled the use of two rings.)

Why a ring-type booster exhaust was sometimes used is unknown. The conventional wisdom is that the booster was used during the first phase of the speed curve, when the main cylinders could not use all of the steam that the boiler was capable of producing using the draft created by the exhaust from those cylinders. Perhaps though in this case – at least for the J-1 - the booster was operated into the first part of the second phase of the speed curve, where steam supply was limiting and the curve tilted over towards becoming a rough approximation to a rectangular hyperbola. (1) In that case, the extra draft created by the booster exhaust may have been of value.

From that one might infer that J-2 operations were typically such that this benefit was not much realized, so were not fitted with the ring-type booster exhaust. That though is pure speculation. For the J-3, with its greater steam producing capability, it evidently did not matter much, such that placement of the booster exhaust appears to have been more a matter of convenience.



(1) A good treatment of steam locomotive curves was provided in the book “The Concise Encyclopedia of World Railway Locomotives”, edited by P. Ransome-Wallis. See chapter 6 “The Testing of Locomotives”.



Cheers,