cab units

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  • Member since
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Posted by RailfanGXY on Tuesday, February 20, 2018 5:57 PM

The F7's had them too?

MidlandMike

 

 
RailfanGXY

...

F7: Full-width cab units

FP7: Full width cab unit equipped with steam heating

...

 

 

 

F7's had a steam generator option.  FP7's simply were 4' longer to accomodate extra steam generation capacity.

 

 

Okay, I kind of understand that with the boosters (the same program explained that on the Santa Fe, only the B-units were equipped with steam generators). I'm slightly surprised that F7A's had them as well, considering how short they were lengthwise. Then again, they could just have them installed and not be able to have them work without the water supply in the B-unit...

I dunno, I've never seen plain F7's working a passenger on their own without a B. At least, not until the 1980's when some railroads began equipping them with HEP for commuter service.

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Posted by MidlandMike on Tuesday, February 20, 2018 9:35 PM

Overmod

 

 
MidlandMike
FP7's simply were 4' longer to accommodate extra steam generation capacity.

 

You mean to accommodate extra fuel and water for steam generation capacity, right?

 

My source was the Second Diesel Spotters Guide.  "...lengthened to supply extra steam generator and water capacity for passenger service."  They show a photo of a Frisco FP7, but it does not look like in this case they utilized all the extra space underneath for extra (fuel) tank space.  Here is a picture of a Reading unit that has a similar tank arrangement:

https://www.trainspotted.com/photo/1245-Reading-R-903-diesel-locomotive-EMD-FP7

 

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Posted by BaltACD on Wednesday, February 21, 2018 6:52 AM

The B&O had a series of steam generator equipped F3's.  They were purchased to head up the streamlined Columbian and other trains.  In use it was found that the water capacity for the steam generator was insufficient.  In real world use on the Columbian, with the engines being fueled and watered at the Robey Street coach yard in Chicago - the train being taking to Grand Central Station for passenger boarding and then the trip to the crew change point of Garrett, IN - the engines would arrive with the steam generators shut down - OUT OF WATER.  The engines would be watered at Garrett and complete the rest of the run with watering facilities that had been established for the E units that hauled the bulk of B&O's diesel passenger service.

With the Western carriers having longer runs than the 150 miles from Chicago to Garrett, I am certain the F series units that these carriers used had additional water capacity.

         

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Posted by M636C on Wednesday, February 21, 2018 7:02 AM

MidlandMike

 

 
Overmod

 

 
MidlandMike
FP7's simply were 4' longer to accommodate extra steam generation capacity.

 

You mean to accommodate extra fuel and water for steam generation capacity, right?

 

 

 

My source was the Second Diesel Spotters Guide.  "...lengthened to supply extra steam generator and water capacity for passenger service."  They show a photo of a Frisco FP7, but it does not look like in this case they utilized all the extra space underneath for extra (fuel) tank space.  Here is a picture of a Reading unit that has a similar tank arrangement:

https://www.trainspotted.com/photo/1245-Reading-R-903-diesel-locomotive-EMD-FP7

I think at least some FP 7 and FP 9 units had a vertical cylindrical tank on the centreline internally between the main generator and the electrical cabinet.

Santa Fe who never used FP units, always had the steam generators in the B units, and these might have had internal water tanks as well.

Peter

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Posted by CSSHEGEWISCH on Wednesday, February 21, 2018 10:00 AM

BaltACD

 

With the Western carriers having longer runs than the 150 miles from Chicago to Garrett, I am certain the F series units that these carriers used had additional water capacity.

 
Northern Pacific had baggage cars with water tanks for the steam generators on the F7/9's.  Great Northern may have had a similar arrangement.
The daily commute is part of everyday life but I get two rides a day out of it. Paul
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Posted by Shadow the Cats owner on Wednesday, February 21, 2018 5:27 PM

The Santa Fe had the A units of all their passenger F units carrying a water tank were the steam generator was supposed to have gone.  The B's carried a tank up front and the generator in the back.  

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Posted by BLS53 on Wednesday, February 21, 2018 9:03 PM

challenger3980

 

 
BLS53

I never understood why it was believed that cab units were optimum for freight use. Seems a logical evolution from steam, would've been the road switcher to begin with.

Always thought the RR's were attempting to emulate airliners in appearance with cab units. About all these units had going was their looks. 

 

 

 

 

Because the "F" units were the original road diesel, and came out 10 years before the "GP" units.

The FT was released, IIRC, in 1939, the GP7, the first of the GP's was released in IIRC, October of 1949, for 10 years there WASN'T any other choice, at least from EMD. The Alco RS 1 came out in 1941, so even there it was 2 years before the railroads had a road switcher option.

The road switcher simply wasn't an option, "To Begin With".

Doug

 

You're missing my point. I know the historical evolution. I'm stating given the likeness in configuration between steam and the diesel road switcher, one would think that the operational advantages would have been apparent when the first diesels were designed. The F's and E's were strictly chosen as a marketing ploy in aesthetics. The RR's were going down at the hands of the airlines, and they wanted something that resembled the nose of a DC-3. 

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Posted by M636C on Wednesday, February 21, 2018 10:00 PM

You're missing my point. I know the historical evolution. I'm stating given the likeness in configuration between steam and the diesel road switcher, one would think that the operational advantages would have been apparent when the first diesels were designed. The F's and E's were strictly chosen as a marketing ploy in aesthetics. The RR's were going down at the hands of the airlines, and they wanted something that resembled the nose of a DC-3. 

No.

The cab unit allowed maintainers to fix things en route.

The FTs were built with the first 567 engines. The 567s were dramatically more reliable than the 201A. See McCall's "Santa Fe's Early Diesel Daze" and more authoritively Eugene Kettering's ASME paper on the development of the 567.

Also, there was a war on and changes were not looked on favourably.

So the FT became the standard freight unit basically by default. It was much more reliable than the EA to E2 series of passenger units, but not even EMD could have predicted that in 1939. Hundreds of them were built and the railroads liked them. Post war, they were even happier with the F3 and F7.

By this time Dilworth had realised that the power equipment was now reliable enough to put it in a hood body, since it could run without needing attention during the journey.

Alco Fairbanks Morse and Baldwin made the same change somewhat earlier, but perhaps without the degree of justification that EMD had by the time the GP7 appeared.

The change from a steam locomotive to a hood unit did occur on roads that were late converting to diesel. N&W never owned a cab unit, although they leased some.

But the cab unit was a neccesity in 1937  for the early E units and Rock Island's TAs.

Illinois Central had some big transfer units that were effectively FTs with hood bodies, but they never strayed far from a workshop, even though in retrospect they probably could have run main line freight.

Peter

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Posted by Shadow the Cats owner on Thursday, February 22, 2018 5:42 AM

Another reason why cab units where preferred at first over Road switchers types aka GP or SD types was due to the Railroad worker Unions themselves.  They tried to demand that every cab in the consist have a engineer and fireman in it even if it was the trailing unit in the consist.  They were so bent on demanding this that Santa Fe reworked their first orders of FT's into A-b-b-b units with only 1 cab to stop the unions.  UP did the same with their E units for a long time.

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Posted by Miningman on Thursday, February 22, 2018 8:26 AM

M636C--- N&W did own cab units! They got them from the Wabash absorption and they operated in Canada. 

CN diesel shop Fort Erie. N&W 3657 first unit of a 20 unit order. ex Wabash 657 nee 1155.
GMD A125 November 1950

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Posted by BaltACD on Thursday, February 22, 2018 8:31 AM

Miningman
M636C--- N&W did own cab units! They got them from the Wabash absorption and they operated in Canada. 

CN diesel shop Fort Erie. N&W 3657 first unit of a 20 unit order. ex Wabash 657 nee 1155.
GMD A125 November 1950

N&W owned cab units through their acquisition of the Wabash, however, they never BOUGHT any new cab units.

         

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Posted by Miningman on Thursday, February 22, 2018 8:42 AM

Well yeah, thats what I stated. They got them thru the absorption of the Wabash from/for their operations Detroit--Buffalo running through Southern Ontario. M636C stated theynever owned any. Maybe they did not buy any but they sure owned about 20 of them and for a long time. 

These fellas came thru my adopted home town daily with their nice little red bopper caboose trailing. The Wabash paint scheme was much classier.

664 part of 20 unit order F7A built as 1155, 1155A to 1164, 1164A 
(A125 - A144 11/1950 - 3/1951) this was C-106 the sixth order for GMD. 

670 part of 20 unit order 657-676 

WAB 725 (GMD A487 3/1953) first of two F7A unit order meeting CNR 3875 at Canfield Junction. 
5/18/1966 Peter A. Cox

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Posted by M636C on Thursday, February 22, 2018 4:25 PM

Miningman

M636C--- N&W did own cab units! They got them from the Wabash absorption and they operated in Canada. 

CN diesel shop Fort Erie. N&W 3657 first unit of a 20 unit order. ex Wabash 657 nee 1155.
GMD A125 November 1950

 
Indeed I should have said that N&W never puchased any new cab units.
I guess technically the Virgininan electrics were cab units as well.
 
My intention was to point out that the N&W itself purchased roadswitchers with steam generators for passenger service and never purchased new an E unit or an F unit. The reason for this was that roadswitchers were established by the time N&W stopped using steam on the main line.
 
Contrast this with ATSF who were among the very first purchasers of main line diesel locomotives (with units 1A and 1B, later 1 and 10). They were among the earliest users of hood type switchers as well but these didn't require maintainers to work on them when they were under way.
 
It was this last requirement and the relatively poor reliability of the 201A engine for ATSFs long distance passenger services that caused them to buy cab units and a combination of factors connected to WWII that meant they bought hundreds of FT units for freight. As a result, they kept buying F units for both freight and passenger, although when the FTs were traded in, they got GP30s and GP35s.
 
Peter
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Posted by CSSHEGEWISCH on Friday, February 23, 2018 6:52 AM

While the FT's were traded in for second-generation power, Santa Fe went a different route with the F3A's and F7A's and rebuilt a fair number (200+) of them into CF7's at Cleburne.

The daily commute is part of everyday life but I get two rides a day out of it. Paul
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Posted by NDG on Saturday, February 24, 2018 4:57 PM

 

Water Tank GM FP Unit.
 
FWIW.
 
The round tank behind the front truck is for S/G water, as here.
 
 
Water can be seen dripping out from filler.
 
Some CNR cab units had ' Sponson Tanks ' for S/G Water along outer side of walkway next to Diesel Prime Mover against outer wall.
 
Thank You.
 
 

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