Many railroads, like the Santa Fe, never had full-width diaphragms.
The 1951 GN Empire Builder was delivered with full width diaphragms. The 1955 dome coaches were not. I've got a picture somewhere that shows a GN sleeper with full width diaphragms in about 1956, if I recall properly.
The 1948 North Coast Limited was delivered with full width diaphragms. The Loewy 1954 train did not have them.
Union Pacific dumped full width diaphragms by the end of the forties.
For your favorite road, photographic evidence is best. Different railroads had differing speeds of removal.
Ed
John,
Full width diaphragms didn't last long on many roads after World War II because they were expensive and a maintenance nightmare, especially when passenger service was fast becoming a liability.
These are the answers I would have guessed but my google search didn't get any hits for prototype information. It all dealt with installing diaphragms on model trains. I have a couple of passenger cars with narrow diaphragms that have the same livery as the 1938 20th Century Limited set I bought from MTH. The latter has full width diaphragms. My layout is freelanced and the cars don't represent the 20th Century Limited. I wanted to add a few coaches to the consist and wanted to confirm whether or not it would be prototypical to combine the two types of diaphragms.
The full-width diaphragms gave a better 'streamlined' appearance to the train. They nominally improved streamlining, but then so did underbody skirts and pans.
All the ones I'm aware of that were intended to be run with conventional cars had compatibility with narrow diaphragms. Looking at the ends they have a central 'striker' area around the end door as well as the outside seal.
Something I don't know is if a full-width diaphragm mated to a narrow one had as good weather resistance as two narrow ones.
John-NYBW 1. What were the advantages/disadvantages of full width diaphragms over the narrower ones?
1. What were the advantages/disadvantages of full width diaphragms over the narrower ones?
full width diaphragms lessened aerodynamic drag and also visually unified the train and were also "the latest thing"
OTH, they made working around the car ends more difficult and likely cost more to install and maintain
2. Could a narrow diaphragm be connected to the full width kind?
Yes.