locked Re: F-Unit Roof Hatches

George Eichelberger

I have to agree with Scott’s “doesn’t make it correct” comment. “Improving engine room ventilation" does not make sense to me. If the “thing” housed a fan for ventilation, why not use a standard hatch mounted fan? I doubt it would be pulling air out of the carbody as that would be competing with air for the engine and cooling the DB grid that came in through the grilles. I guess putting more air into the unit could be useful but maintaining filters up on the roof would be a maintenance headache.

According to the order specifications, the unit was built with a steam pipe but no steam generator. Most F units were ordered that way so steam could pass through them (not all had connections) when operating in consists and so that stand-by steam could be used to prevent winter freeze ups. (If there is any interest, I’ll put one of the F unit Specifications on the file server.)

My first thought was that it was a roof mounted water tank. They were needed because of the distance between stops for water.

Since receiving Dale’s request a few days ago, I have been going through the diesel memos and letters we have scanned….none make reference to Sou 4260 or anything unusual.

Here’s a reduced size version of Southern drawing DL-2097 for a 500 gal roof mounted water tank dated July 25, 1952. 

(There are presently 962 scanned diesel drawings in the SRHA digital files, and many more not yet scanned. If this kind of “nuts and bolts” subject is of interest to anyone make plans to A: Join SRHA and B: Come help in the archives.)


On Dec 1, 2019, at 1:39 PM, D. Scott Chatfield <blindog@...> wrote:

An attempt to improve engine room ventilation. Answer is on P.338 of Diesels of the Southern Railway 1939-1982 (Withers with Calloway and Wilson).

Just because it's in a Withers book doesn't make it correct.

I don't see how it would help "engine room ventilation."  F-units did not have pressurized carbodies, and I don't see any vents on the box.  Also note the box is on the front of the NP B-unit and the rear of the Southern A-unit.

To me the box looks like a roof-hung water tank from a passenger-equipped unit, but neither of these units were passenger-equipped.  No pass-through steam lines either.  Perhaps it was a water tank and they couldn't mount it flush because of something inside.

Doesn't appear to hold radio gear either.

So that leaves us with the only logical explanation:  increased headroom so basketball players could use the toilet.

Scott Chatfield

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