DateTime
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Author
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Posting
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09/10/02 9:42 |
Bill Kuebler |
I'd love to > hear from > someone who knows exactly how these appliances > functioned. It appears > they may have had something to do
with steam generation on >
passenger > units, but that
doesn't comport with their appearance on
> freight F-9s. I doubt
very much that they had anything to do with steam generators, at least not directly. There were too many NP units that never saw passenger service
and, thus, never had steam generators
that had these cooling coils. Although it
is possible this roof appliance was for some other system, the coil appears to be cooling piping
associated with the air brake system.
If so, they are there to provide a way of
cooling compressed air or, if there are other cooling coils elsewhere on the unit, they provide
additional cooling for compressed
air. The coil provides a long pipe that, by its very length, permits sufficient heat transfer from warm, compressed air to atmosphere as that air
flows through the pipe on its way to
either a reservoir or a cylinder, as the
case may be. As air is compressed, it warms up considerably, and before the compressed air is used in
the air brake system, it usually has
to be cooled first (and water drained
as the air is cooled). There are a number of places that such a cooling pipe can exist on a diesel
unit. If you study other models, and
the manuals that depict their design,
interiors, etc., you will see these cooling devices on almost every unit, in some location. In
some cases, even though units already
had them, more cooling was thought to
be needed, so additional cooling coils were added somewhere else on the unit, to improve the
compressed air system. The question
then becomes, "Why here and not elsewhere?" for a given cooling coil. The answer to that can
have to do with lots of things,
especially regarding NP's F-units. Two items
come to my mind that might have had something to do with the roof placement on SOME units: water tanks
along the A-units' sidewalls (wall
tanks, as crews called them), and the
presence of a steam generator or associated equipment taking up space that otherwise could have been
used for additional compressed air
cooling. NP added sidewall water tanks to all its passenger F-3/5/7/9 units shortly after delivery. NP
was very big on carrying lots of
water and minimizing water stops,
especially after 1952. The water-baggage cars on trains 1,2,25,26 indicate this. > > > Here's what I have gleaned so
far: > > 1) All F-9 As and Bs, in freight and passenger
service, > appear to have > been equipped with rooftop cooling
coils on delivery in >
1954-56. I agree. >
> > 2) Some
earlier-model F-units in passenger service were > subsequently >
retrofitted with rooftop coils when shopped. The earliest > photos for > which I have seen retrofit roof coils are from 1961
(F-3B > no. 6504B) > and 1962 ( F-7As no. 6506A and 6508C,
F-3B no. 6509B). You can add the
years 1958 (6507B) and 1959 (6507A) to that
list. See my list of individual units below. > By the >
mid-1960s, a good share (but not all) of NP's F-3 and F-7 > units in > passenger service had received roof coils. It appears
the > two FP-7As > never had them and perhaps the
so-called F-5s didn't >
either. I recall no photos of an
FP-7A that show the roof coils, but I
do recall seeing one of an F-5A (6506C) that has it--taken at Fargo in 1966. Can't put my finger on
the image at the moment, but the view
stands out vividly in my mind, so am
adding it to my list below. The image stands out so vividly account the occasion. The malfunctioning
unit had been taken off train No. 1
and the photo shows the lonely A-unit
standing on an aux track west of the 13th Street Underpass, a very unusual scene. >
> > 3) Freight service
F-3s, F-5s and F-7s did not appear to
> be fitted > with roof
coils, with at least one exception.
Four exceptions: 6005C; 6005B (re# 6553B in 1962); 6006B (re# 6551B in 1959); and 6006C (re#6552B
in 1960). All four were originally
passenger F-3Bs from original sets
6503-6506. > Venerable
F-3B no. > 6005C was captured in
1965 (Kuebler p. 110)sporting a >
distinct set of > roof coils, but
the unit appears freshly painted in
> black-and-yellow >
livery. If you look closely, I just now noticed, you > can even make > out the top of a steam generator vent
cap poking up from > the hind
roof > panel,
passenger-style. This is correct,
although the steam generator itself had
been removed. Some (or most) of the fittings and piping were left in the unit, however. Ditto the other
three ex-passenger F-3Bs listed in
the preceding comment, all three of
which were converted back to passenger service, and steam generators re-installed, as indicated. The fresh
paint on the page 110 photo is simply
account a standard repainting job as
part of the routine, four-year major
maintenance program. >
This suggests to me that unit 6005C might
> have done some time in passenger service shortly before or > after 1965, > but I have found no record of such in my reading. See above two comments and the note for
this unit in the list below. >
> > The take-home
message for modelers seems to be: If you
> are doing a >
1960s-era F-3 or F-7 in passenger colors, you had better > find a > prototype photo of the unit you're modelling if you
want > to make sure > to get the roof nits correct. Exactly, but add F-5A to the models you
listed above, and include the 1950s
era as well. More comments about this
below. Meanwhile, to help you modelers do this, I have a list for you below that you might find
useful. > Otherwise, if you're
modelling a freight > unit, leave
roof coils off, unless it is an F-9, or 6005C or any of the other three ex-passenger F-3Bs (6005B,
6006B, 6006C, or their pre-1/50
freight numbers) > --then
do > them. > Note: 6005C might have possessed
all the customary > steam > generator appendages while in freight
colors, but the > freight
F-9s > didn't--they just had the
coils, with the hind roof panel >
blind. Correct, except for two
ex-passenger F-9As (7051A and 7052A),
which still had some steam generator fittings in them. Unit 7051A went back to passenger service as 6705C
in 1966. When it comes to "patterns" regarding NP
F-units' appearances and appliances,
there were very few consistent
patterns. In almost every "pattern" there were exceptions
at one time or another, on one unit
or another. As for the cooling coil
discussed in this thread, the moment you think there might be a pattern, along comes a photo to prove it wrong. Therefore, *look at photos* to be
sure about your work. I just went
through many of my F-unit color slides (I
didn't even bother with my photo collection, for it is much larger, less organized, and it is probably
unnecessary to look into it anyway,
account the slide collection being
sufficient for this purpose). A list appears below of only those units where the angle of view of the
left side of the unit is such that
the matter of the coil being present or
absent is certain, except the one or two noted otherwise. Bottom line: these images are conclusive
regarding the units indicated on the
dates shown. For the freight
F-3/5/7 units, I intentionally focused
mostly on late dates, since that would show no retrofitting and probably cover the unit's entire NP
service life. For freight F-9s, I
looked at all my slides, since these units
were very consistent. For passenger F-3/5/7s, I focused mostly on the 1954-64 period, since that
seems to more than cover the period
of any retrofitting. For passenger F-9s, I
looked at all of them, again to cover their entire NP service lives. Individual units are listed, along with the model type
and month/year of the image. A
"YES" means that there is most
definitely a cooling coil on the left side of the roof fans. a "NO" means that there
definitely isn't. Again, the angles
of the views, unless noted otherwise, are good enough to be certain of the matter. For freight units,
I've grouped them by model, but watch
out for the passenger units, for
different models are mixed into same-number series groups, as they are more difficult to break out.
Here's what I found: FREIGHT UNITS: 6000A F-3A 8/65 NO
6000D F-3A 8/67 NO 6001A F-3A
8/62 NO 6002B F-3B 7/65 NO 6003A F-3A 7/65 NO 6003B F-3B 10/66 NO 6003D F-3A 8/68 NO 6004A F-3A 8/62 NO 6004B F-3B 8/67 NO 6004C F-3B 8/62 NO 6005C F-3B 8/65 YES (former Pass 6503C
(1st); Frt 6016C (1st) 1948; Frt
6005C (2nd) 1950) 6005A F-5A 7/54
NO 6005A F-5A 8/62 NO 6051A F-5A 3/67 NO (ex-6006A) 6052A F-5A 6/68 NO (ex-6006D) 6010A F-7A 9/67 NO 6010C F-7B 7/65 NO 6011A F-7A 8/69 NO 6011D F-7A 8/61 NO (Note: This unit
wrecked in 9/54, reblt. 10/54 - 2/55,
re-entered service with same number,
but some minor differences on unit; still no coil, however) 6012A F-7A 8/62 NO 6013D F-7A 6/70 NO 6014D F-7A 8/68 NO 6015A F-7A 2/70 NO 6015D F-7A 2/70 NO 6017A F-7A 8/68 NO 6017D F-7A 7/65 NO 6018D F-7A 8/67 NO 6019A F-7A 8/67 NO 6019C F-7B 8/70 NO 6019D F-7B 6/68 NO 6020D F-7B 6/68 NO 6050 F-7B 7/68 NO (Note: this was 6050B,
but the large-size B suffix was never
put on the rear flanks) Freight
F-9As and F-9Bs in 7000 series: YES I have photos of most in the fleet, 1954-70, too many to list individually. Every pic showing left side
roof shows the cooling coils. This
includes the two F-9As that were
originally passenger units: 7051A (formerly 6703A (1st)) and 7052A (ex- 6704A 91st)). It is most likely
that these units were delivered with
the coils or had them added by NP upon
delivery from EMD. PASSENGER
UNITS: 6500A F-3A 5/63 YES 6501C F-7A 7/61 NO 6502A F-3A 10/48 NO 6502B F-3B 10/48 NO 6502A F-3A 7/66 YES 6504C F-5A 4/62 NO 6505A F-3A 9/65 YES 6506A F-3A 4/66 YES 6506C F-5A 4/61 NO 6506C F-5A 6/66 YES (this is the only
image on these lists that I have not
just looked at, but am including it
here account it being so vivid)
6507A F-7A 8/59 YES 6507B F-3B
4/58 YES 6507C F-7A 7/65 YES 6508A F-7A 7/57 NO 6508A F-7A 12/61 NO 6508A F-7A 3/62 PROBABLY (this image shows
the unit very heavily damaged, just
after being pulled from Granite Lake
following a derailment of train 25. The damage is so great that the presence of cooling piping is in
question, but I believe it is
there.) 6508C F-7A 7/66 YES 6509B F-3B 10/65 NO 6509C F-7A 5/67 NO (angle is a little low,
so there might be a coil, but I don't
think so) 6509C F-7A 7/69 NO (angle
is high enough here to be certain--no
coil) 6510A F-7A 8/62 YES 6510B F-7B 8/62 NO 6510B F-7B 9/68 NO 6511A F-7A 5/56 NO 6511B F-7B 5/56 NO 6511B F-7B 7/66 NO 6511C F-7A 6/52 NO 6511C F-7A 2/58 NO 6511C F-7A 7/65 YES 6512A F-7A 8/62 YES 6512C F-7A 6/61 YES 6512C F-7A 7/65 YES 6513A F-7A 10/54 NO 6513A F-7A 3/61 YES 6513C F-7A 7/65 YES 6551B F-3B 5/63 YES (ex- 6505B (1st);
then 6017B (1st) 11/48; 6006B (2nd)
1/50; 6551B 1959) 6553B F-3B 4/66 YES
(ex- 6504B (1st); then 6016B (1st)
11/48; 6005B (2nd) 1/50; 6553B 1962) 6600 FP-7A 6/66 NO 6601 FP-7A 9/60 NO
6700s F-9A and F-9B units. Every one appears to have had the cooling coil for its entire NP life,
including all former freight F-9s
that were converted to passenger service
during the 1964-67 period (there were several). I.e., conversion from freight to passenger was
not a factor. Judging from the
above image list, the passenger F-3/5/7
conversion seems to be mostly (but not exclusively) on A-units, and took place during the period,
roughly, 1958-1963. The only
significant thing that happened to NP's
passenger F-unit fleet during that period having to do with the brake system, that I know of, was the
discontinuance of the
electro-pneumatic brake system in May 1962, and the consequent removal of all its parts by June 1964. These dates don't match the retrofit period
suggested above, nor can I think of a
reason for the removal of the
electro-pneumatic system having anything to do with this cooling coil. Assuming that the coil was,
indeed, associated with cooling compressed
air, I would guess that NP simply
tried to improve cooling on many units, but not on all of them. As is often the case with such
matters, limited funding was probably
a factor. One other thing regarding
passenger service and brake systems:
NP operated its passenger trains with 90 P.S.I. brake pipe pressure, and its freight trains with 70 P.S.I. Each of these figures was 20 P.S.I.
greater for service in mountain grade
territory. The brake pipe pressure nominal
value was determined by the locomotive engineer, who would set his feed valve in the cab accordingly.
This may have had something to do
with the coil, but that is doubtful, as
there are too many inconsistencies in the above listings to draw a relationship between coil and brake
pipe pressures. Bill Kuebler PS: This took me a while! Anybody out
there who wishes to take some time to
reciprocate and to, say, post some images
or something like that, please do. Especially images showing this roof coil feature! F3, F7, F9, Compiler C Frissell |
|
01/20/03 22:24 |
Chris Frissell |
For those of you
interested in the minutiae of NP diesel history, I have spent some time adding to Bill Kuebler's list of the
occurrence of rooftop cooling coils
on NP F units. Bill posted his list last
year here based on his personal photo collection, and I have added
to it with records from published
photos in the NP books I have
available. I started on this a while back, but was waiting for
the Dale Sanders NP book to some out
before finishing a first cut at a
comprehensive list. For those few who are into this, here is link
to the document with the complete
list, which I have posted in the Files
section of the NPTelltale Group. I will also copy the description
and summary from that document below
so you can get the gist of the list:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ROOFTOP COOLING COILS ON NORTHERN PACIFIC
F UNITS AS OBSERVED ON HISTORIC
PHOTORAPHS How the List was
Compiled This list is a working
record of historical documentation of the
occurrence of rooftop cooling coil appliances on the EMD F-units
of Northern Pacific Railway. Un-cited
entries in plain text are Bill
Kuebler's, from his photo collection and recollection. Entries in italics are Chris Frissell?s additions
from published photo sources, as
cited. The table lists engine number, model, date of photograph, YES for rooftop coils definitely present,
NO for rooftop coils definitely
absent, and notes, with sources and (for most records) page numbers cited in parentheses as noted
above. Full citations for the
published sources are given at the end of the document. The following criteria were used to
screen published photos: Photograph
should show a clear view of the fireman's side of the roof, where the cooling coils are installed, if
present. Engine number should be
clearly evident on the photo, or else positively documented in the photo legend and verifiable by
engine type, paint, and service. Date
at least to year is provided in the photo legend. Photos that, based on month of image and engine number,
were likely redundant with Kuebler's
photo records are not listed. As
Kuebler notes, all F-9s delivered from EMD, both freight and passenger units, appear to have been
equipped with rooftop coils upon
entering NP service. Therefore this list only records
observations of earlier-model F
units, in order to help establish the history of retrofits of these earlier models, none of which were
originally delivered with the rooftop
coil appliance. Please submit
additional entries, corrections or suggestions via the NPTelltale Yahoo Group, or directly via
e-mail to Chris Frissell,
hanfris@d... Summary The list presents data on about 38
freight units and an equal number of passenger
units for which good documentation is available. Multiple records for some units allow a rough reconstruction
their history. Allowing for gaps and
making some extrapolation, it appears
that many F-3, -5, and -7 units in passenger service were
retrofitted with rooftop coils
between about 1958 and 1963, and possibly some a year or two earlier (the F-9 units were acquired from EMD in
1954-56, so by 1958 the NP crews and
shops would have had several years of
experience with coil-equipped units). Units dedicated to freight service were not retrofitted. The single
observed exception to this rule, F-3B
No. 6005C, was swapped between freight and passenger use over the years, and while in freight
colors also retained steam generator
vents on her rear roof panel. With
one possible exception, units that gained rooftop coils apparently retained them for their service
life. The possible exception is
passenger F-7A 6513C, which was reported by Kuebler from his records to show a coil in 1965, but
does not have a coil in two clear
published images from 1967. The NP
did not retrofit all passenger units with coils, but did most of them. By 1965, for the passenger units
having sufficient data in this list,
5 F-7s and one F-3B did not have rooftop coils, in comparison to 21 F-3s, -5s, and -7s known from the record to
have been retrofitted by that year.
It is unknown why some units were not
retrofitted with rooftop coils and others were, but it seems
plausible that this was simply a
consequence of shop scheduling for major
overhauls, coupled with a decreasing demand for passenger power in
the late 1960s that might have
diminished the benefit to the railroad of
upgrading older units. By 1965 the NP had begun to trade in older passenger units to GE and EMD toward their
purchases of second-generation
freight power. Although this is
only a partial survey of published and Kuebler's collected photos of the Northern Pacific Railway's F-3, -5 and
-7 diesels, it is interesting to note
there is much of variation in the
frequency with which individual units appear in photographs. The most-often-photographed freight unit on
this list was F-5A No. 6005A (caught
in four rooftop coil exposures). Passenger units on average appear to be more popular, or perhaps less
shy, with F-7As No. 6513A and 6512C
each showing in five separate rooftop coil poses. F3, F7, F9, Compiler C
Frissell |
|
01/23/03 17:48 |
Bill Kuebler |
I have spent some time adding to Bill
Kuebler's list of the >
occurrence > of rooftop cooling
coils on NP F units. After glancing
over this file, I see one item that needs a
slight correction. Regarding passenger F-7A 6500C, your note says that after its wreck in 8/55, it was
rebuilt to F-9 6703C. Actually, the
original number, 6500C, was retained on
the "new" F-9A from early 1956 until 1965, when the unit
was finally renumbered 6703C to
integrate it into the 6700 series. As
far as I know, the number was the only thing that changed on that unit in 1965. During 1956-65, the 6500C
was the only F-9A in the 6500 series.
Long story about this, but for now
you might want to note that number change in the document so as to avoid any confusion. F3, F7, F9, Compiler C Frissell |