reason for elevated "roof " on heavyweight passenger coaches?

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reason for elevated "roof " on heavyweight passenger coaches?
Posted by Paddy M on Tuesday, May 26, 2020 9:29 PM

See subject line for question

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Posted by MidlandMike on Tuesday, May 26, 2020 9:37 PM

I presume you are talking about clerestory roofs.  They originally had little window/vents on the short vertical side that could be opened for ventilation.

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Posted by Convicted One on Wednesday, May 27, 2020 3:11 PM

MidlandMike
I presume you are talking about clerestory roofs.  They originally had little window/vents on the short vertical side that could be opened for ventilation.

 

I have no doubt that you are correct. I also wonder if it was for additional headroom in the aisle?

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Posted by ATLANTIC CENTRAL on Wednesday, May 27, 2020 3:25 PM

Heat rises, the design provided natural air flow out the vent windows that aided in improved comfort.

The glass vent windows in the earliest cars also provide improved aisle lighting in daylight.

Headroom was not really an issue, the lower roof over the seats was more than tall enough. But, going back to my opening comment, just like taller ceilings in older homes, the extra headroom provides a place to pull the warmest air away from the people, including those walking in the aisle.

Designers and Architects understood convection cooling pretty well back then.

Sheldon

    

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Posted by MidlandMike on Wednesday, May 27, 2020 8:25 PM

Excerpts from a book on Google Books rgarding passenger car archetecture says that the clerestory roof just be came an excepted standard, despite its weakness compaired to an arch roof.  Harriman arched roofs just had vent risers on the roof.  Eventually some clerestory roofs got partially rounded off by the addition of air condition ducts.

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Posted by Convicted One on Wednesday, May 27, 2020 8:41 PM

Then you got these:

 

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Posted by ATLANTIC CENTRAL on Wednesday, May 27, 2020 9:00 PM

MidlandMike

Excerpts from a book on Google Books rgarding passenger car archetecture says that the clerestory roof just be came an excepted standard, despite its weakness compaired to an arch roof.  Harriman arched roofs just had vent risers on the roof.  Eventually some clerestory roofs got partially rounded off by the addition of air condition ducts.

 

They are referring to later steel cars without clerestory windows, just vents.

After the indroduction of A/C in the 30's the inside of the clerestory was often converted to ductwork space and additional ducts were added to the lower roof exterior, rounding off all or part of the roof.

Pullman was by far the largest car builder and the steel cars of the first part of the 20th century were built from standard parts. Yes, Pullman and others were reluctant to change the design until streamlined cars became the norm.

Weakness? I don't see where or why that would be an issue?

Heavy weight cars of this era had steel framed floors filled with concrete like an office building to prevent cars from telescoping and limit roll overs in crashes.

Sheldon     

    

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Posted by Gramp on Wednesday, May 27, 2020 10:14 PM

Did heavyweight cars ride more smoothly?  I recall that people would try to not be seated over the trucks. 

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Posted by ATLANTIC CENTRAL on Wednesday, May 27, 2020 10:55 PM

Gramp

Did heavyweight cars ride more smoothly?  I recall that people would try to not be seated over the trucks. 

 

Compared to the first lightweight streamliners, yes, heavyweight cars road much better.

It took a while for designers to get smoother riding lightweight designs perfected. And some of those early streamliners were only a little "lighter" than the heavyweight cars.

In 1935 the B&O bought two streamlined train sets from American Car and Foundry. One for the Alton's Abraham Lincoln and the other for the Royal Blue. They were not happy with the ride, by 1937 the Royal Blue set was sent to the Alton to supplement the Abraham Lincoln/Ann Rutledge service.

Rather than buy any more new lightweight streamlined equipment, the B&O rebuilt their heavyweight cars into streamliners, but underneath they remained traditional heavyweight cars.

While some more modern cars were purchased later, the B&O did fully embrace modern passenger cars until the C&O took control in the 60's.

Many heavyweight cars were rebuilt and upgraded but retained their core construction and remained in service until the decline of passenger trains.

Sheldon

 

    

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Posted by Erik_Mag on Wednesday, May 27, 2020 11:28 PM

ATLANTIC CENTRAL

Weakness? I don't see where or why that would be an issue?

A continuous arch roof is stronger than a clerestory roof of the same weight. The stiffness in heavyweight cars was primarily provided by the center sill and frame, with the carbody above floor level providing little more than protection from the elements. The sides and roof of leightweight cars provided much of the overall strength and stiffness, with the center sill focused on draft and buff loads.

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Posted by ATLANTIC CENTRAL on Thursday, May 28, 2020 6:06 AM

Erik_Mag

 

 
ATLANTIC CENTRAL

Weakness? I don't see where or why that would be an issue?

 

 

A continuous arch roof is stronger than a clerestory roof of the same weight. The stiffness in heavyweight cars was primarily provided by the center sill and frame, with the carbody above floor level providing little more than protection from the elements. The sides and roof of leightweight cars provided much of the overall strength and stiffness, with the center sill focused on draft and buff loads.

 

Agreed, but as long as the floor was built the old way, there was no incentive to build the roof differently. Although there were a fair percentage of arch roof heavy weight cars, mostly coaches, baggage and RPO cars.

Clerestory roofs were not purposely or neglectfully inferior, it was just a design evolution.

Not sure when the last heavyweight cars were built, but by the mid 30's most new passenger equipment was of a streamlined carbody appearance regardless of exact construction method.

So effectively, cleresstory roofs and the ventilation features were a "pre air conditioning" feature (first air conditioned rail car, 1930, B&O diner Martha Washington).

The desire for art deco streamlining and A/C eliminated the clerestory roof from new railcar construction pretty quickly, but that did not remove thousands of cars from service. Many of which lasted into the 60's, and are still with us today on tourist lines and in museums. 

Sheldon

    

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Posted by 54light15 on Thursday, May 28, 2020 4:55 PM

The celestory roof wasn't just for train cars:

https://www.conceptcarz.com/vehicle/z11537/alco-model-six.aspx 

I've seen this one myself, its impressive. I had a Moto-Meter (the radiator cap thermometer) insert for an Alco car which I donated to the Crawford museum that has this car in their collection. 

 

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Posted by oltmannd on Thursday, May 28, 2020 6:24 PM

I like the ventilation idea.  Great for natural convection when sitting still.  Get forced flow from the venturi effect when in motion.  

-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/

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Posted by MidlandMike on Thursday, May 28, 2020 9:30 PM

ATLANTIC CENTRAL
Weakness? I don't see where or why that would be an issue?

My recollection is thet they were talking about clerastory roofs over wood sided cars at that point.

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Posted by Lithonia Operator on Sunday, May 31, 2020 8:35 AM

Even if the clerestory windows were shut, it was still a place for hot air to rise to. My guess is that seated passengers' heads might be 10 degrees cooler than the air up in the clerestory.

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Posted by ATLANTIC CENTRAL on Sunday, May 31, 2020 8:57 AM

Lithonia Operator

Even if the clerestory windows were shut, it was still a place for hot air to rise to. My guess is that seated passengers' heads might be 10 degrees cooler than the air up in the clerestory.

 

Exactly, it was the right design at the right time. Made obsolete by conditioned air.

Sheldon

    

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Posted by CSSHEGEWISCH on Sunday, May 31, 2020 10:03 AM

Lots of factory and steel mill structures were also built with a clerestory for ventilation reasons.

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 MidlandMike on Sunday, May 31, 2020 8:58 PM

And a lot had windows for lighting the interior away from wall windows.

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Posted by BaltACD on Sunday, May 31, 2020 10:23 PM

MidlandMike
And a lot had windows for lighting the interior away from wall windows.

And the last day the clerestory windows were clean was the day the building opened.

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Posted by 54light15 on Monday, June 1, 2020 9:15 AM

I worked in a factory where there was a celestory running the length of the building. We replaced cracked or broken windows with plywood. The lighting was constantly being upgraded. I wonder why? 

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Posted by daveklepper on Wednesday, June 3, 2020 3:26 PM

 

Passenger railcar construction in North America included clerestories almost immediately upon departure from stagecoach bodies on flanged wheels.  Even single-truck horsecars had them.  But thery were rare in Britain and Europe.  Wagons-Lits sleepers had arched-roofs.  Why the difference? 

 

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Posted by ATLANTIC CENTRAL on Wednesday, June 3, 2020 10:59 PM

daveklepper

 

Passenger railcar construction in North America included clerestories almost immediately upon departure from stagecoach bodies on flanged wheels.  Even single-truck horsecars had them.  But thery were rare in Britain and Europe.  Wagons-Lits sleepers had arched-roofs.  Why the difference? 

 

 

Since I know little to nothing about trains in Britian or Europe, I will not even venture a guess.

Sheldon

    

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Posted by daveklepper on Thursday, June 4, 2020 3:16 AM

Very rare in Israel or surrounding areas also.  If any.

Fiest Israeli-operated train after Independence:

British Nandate era, 1920s:

 Pre-WWI narrow gauge original line:

 

 

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Posted by daveklepper on Thursday, June 4, 2020 3:49 AM

Manx Electric, Isle of Man, an exception:

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Posted by ATLANTIC CENTRAL on Thursday, June 4, 2020 6:35 AM

Maybe Europeans did not mind being hot and uncomfortable?

Maybe they doubted the value of the technology?

Maybe taking an idea from the "colonies" was beneath them?

Come on, they still hook freight cars together with chains, over 100 years after the perfection of the automatic coupler?

Yes, today I am the arrogant American.........

Because I know so little about Euopean trains and fail to understand why they are so seemingly backward?

Sheldon

    

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Posted by 54light15 on Thursday, June 4, 2020 3:19 PM

European passenger cars generally had fully opening windows and lots of roof ventilators. I believe that in the interest of security DB postal cars had celestory roofs if the equipment on my N scale layout is anything to go by. 

 

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Posted by daveklepper on Thursday, June 4, 2020 9:40 PM

That makes sense.

And "Harriman" UP, SP, and RI coaches had lots of roof ventilaters.

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Posted by ATLANTIC CENTRAL on Thursday, June 4, 2020 10:24 PM

As I mentioned much earlier in this thread, there were arch roof cars in North America other than Harriman cars.

In particular many heavyweight baggage and RPO cars, as well as commuter grade coaches.

And yes they had lots of roof vents.

Many roads, like the B&O for example, had a mix of both types of roofs on head end equipment.

The reason for the mixture is obscure at best.

In the era that heavyweight cars were built, generally pre 1930, North American passenger cars also all had operable windows.

Only after cars were modernized in the late 30's or 40's were windows often sealed up.

This thread started out with some bizarre tone/assumption that there was something defective, substandard, or outmoded about the clerestory roof, not realizing that it generally disappeared from new railcar construction about 1930 as streamlined designs and air conditioning took over.

Maybe that comes from a lack of knowledge of the typical life span of a passenger car in the 20th century.

Heavyweight cars built in the teens or twenties underwent numerous rebuilds, many times making them unrecognizable from their original form, but none the less often retaining their frames, floors, trucks and core body structures while making their exteriors match newer streamlined equipment, and bringing their interiors into the latest Art Deco styling. 

For examples, just research the B&O name trains of the late 30's and 40's.

And many also received rebuilds that modernized systems but retained their classic heavyweight appearance, typical of many private office cars that are still around today. 

From the little I know, European passenger equipment bares little resemblance to anything in North America, then or now.

So, it does not surprise me that the clerestory roof was not common there.

Sheldon

    

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Posted by charlie hebdo on Saturday, June 6, 2020 8:44 AM

Very informative post,  Sheldon.  An example of arch roof cars was the CNW aluminum 80' hi-capacity commuter cars of the 20s.  4 or 6 wheel clerestory equipment was seen in Germany,  built prior to 1920, but seen even in the 1950s.

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Posted by daveklepper on Sunday, June 7, 2020 2:29 AM

Lots of PRR P70s, all originally bujlt with cleristiory roofs, were rebuilt into what anyone would assume were lightwieght, streamlined, picture-window, air-conditioned, arch-roof cars.  Indeed, they made up most of the NEC NY - Washington fleet before and into Amtrak.  Of course, there were variations.  A sizeable number kept small, but sealed, windows, and there were even a few with cleristory roofs and picture windows!  All had their original P70 frames.  Some received new drop-equalizer trucks, while others kept their PRR pedistal-arrangement original trucks.

Most long outlasted the all-new 44-passenger long-distance coaches, some of the most comfortable long-distance coaches ever built, but suffering from rust early-on.

The lightweight era did not begin with streamliners.  Stillwells were essentially light-weight, with the whole carbody, including the distinctive roof (neither cleristory nor arch), contributing to buff strength.  Hudson and Manhattan black cars, BMT steels, NYW&B, Erie, London and Port Standley.  Erie's commuter version were built for conversion to electtric mu, which never happened.

Gibbs cars, IRT and LIRR, P70s, P54s and MP54s, NYCentral MUs, H&M-PRR Newark cars, used the side sheets, the sides below the belt rail, as part of structural strength, essentially a gondola with superstructure.  Note that Levin's PRR 120 office car, used by Presidents, was rebuilt from a P70 and still has 4-wheel trucks, unusual for an office car.

And Santa Fe Budd diners, both single-level and El Capitan, had/have six-wheel trucks.

A question.  Original LIRR DC MP-54s had cleristories.  But after about ten years later all new LIRR MP-54s and P54 steam-hauled, had high arch roofs.  But combines were exceptions, new ones had cleristories.  Both MU and steam-hauled.  And the new AC PRR MP-54s, starting with the first Philadelhia-aria suburban electrification, all had cleristories.   Why the differences?

NYCentral MUs all had cleristories up to WWII.  The first NYNH&H MUs were open-platform (but steel) with cleristories.   Then came closed platforms and mu door control, then arch roofs, all before WWII, and without air-conditioning and with operable windows.

Delaware and Hudson had Scranton - Carbondale steel open-platorm, roller-bearing, arch-roof cars.  Pulled by 2-8-0s also used in the local freight service.

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