How many domes?

[pcarrell]

I am modeling the late 30's / eary 40's. I am interested in running a couple of tank cars but I'm at a loss as to what I need.

Single dome without the cage around it and frameless?

Single dome with the cage and frameless?

More domes?

Frames?

I'm guessing single dome, no frame, no cage.

What say you? [?]

[Anonymous]

Domes depend on where you are delivering to. The multi-dome allowed delivery of three different fuels to small local distributers. These seem to disappear when small deliverys make better sense using the Interstate highway system. Rails appeared on some tank cars as early as 1949 but seem to be more dependent on time as they begin appearing with regularity in the 1960's. Frameless were developed in 1954 so appear after that.

[pcarrell]

So there were 3 dome cars right from the start pretty much? I had only seen the single dome cars in old pictures.

Good to know about them needing frames for my era.

Any other info would be great (links, comments, pictures, etc.)

Thanks,

[ndbprr]

Cars are not unloaded from domes they are gravity offloaded for the most part through a valve on the bottom. My understanding is the domes are for expansion of product as it heats up from the sun. Small expansion - one dome , large expansion three or more.

[pcarrell]

Insightful! I hadn't thought about that!

[egmurphy]

Here's a link to a long thread talking about tank car domes, especially multiple dome cars, over on the Atlas N scale forum. I think you might find the info you're looking for here:
http://forum.atlasrr.com/forum/topic.asp?TOPIC_ID=15279&SearchTerms=3,dome,tank,car



Oh, and I believe that tank cars can be either bottom or top unloading, possibly depending on design. Here's a link to a pdf file that includes a diagram on the first page showing both methods. While this particular document is for caustic soda, I believe the principles would be the same for other liquids.
http://www.ppg.com/chm_chloralk/Docs/NAOHTankCar.pdf


Regards

Ed

[pcarrell]

Excellent stuff egmurphy!

Thanks,

[dehusman]

The three domes are there for three different commodities, not for additional expansion. The 3 dome tank cars (which were relatively rare, I have only seen 2 real ones in the last 25 years) had partitions inside the tank to separate the different commodities.

For the 1930's-40's you would want a riveted 8-10,000 gal tank car with a frame. LifeLike P2K and Intermountain have typical cars. The Athearn car is cars is the right style except the dome is way too short. Smooth welded cars and frameless cars are 50's to 60's.

Dave H.

[Jetrock]

Keep in mind that other liquid commodities, like wine, were shipped in dome cars--sometimes with 5 domes!

[pcarrell]

talking to you guys are like drinking from a fire hose!

The LifeLike P2K and Intermountain cars,...is that HO or N scale? I'm in N.

[ericsp]

There is at least on 6 dome tankcar in this photograph.
http://www.snowcrest.net/photobob/sj23.html

[dehusman]

Intermountain and Kadee 39' tank. The Bachmann 3 dome (remember though they are very rare, maybe 1 multiple dome car for every couple thousand single dome cars). The Model power 3 dome (looks better, higher domes than Bachmann) or 40' chemical car. There may be others, I'm not an N scale modeler.

Dave H.

[pcarrell]

Gulp, gulp, gulp, gulp,...

[dknelson]

Unless you are lucky or wealthy or both you are unlikely to have Car Builder Cyclopedias from the 1920s, 30s and 40s. But with a bit of searching at swap meets you can buy the Train Shed Cyclopedia No. 12 "Tank Cars 1922-1943" which has photos and plans of many tanks cars some of which became commercial models such as the Athearn/"Crown" (99 cent) three dome Deep Rock tank

Most cars were single domes. Many multiple dome cars carried different commodities in different compartments, and presumably the six dome wine car shown in the book had 6 varieties of wine inside.

But there were also multi dome cars which carried all the same commodity -- perhaps also stored in compartments as a hedge against impurities, or to ease unloading or to ease loading.

The domes were the loading source but also where pressure could be hooked up for faster unloading by the way.

The book shows an American Cyanamid 3 dome tank said to be for dry powder loaded through three domes and unloaded through six discharge hoppers for example.
Dave Nelson