Year of build.

Short answer: A lot of the first container cars were built for 40ft containers. As containers and trailers were granted longer sizes, the container cars were also built to accommodate the larger containers and trailers

Container cars

Well, yes, they used to load containers on single-level flatcars.

This worked well for standardized 40' and 20' containers, and also fit into any height restrictions.

Then the developed the double stack well car, with a depressed body and heavy side frame to hold the lower level of containers as low as possible in order to allow stacking two levels of containers. This greatly increases capacity over single level, even though the car body must be longer because now the trucks are outboard of the ends of the containers instead of under them.

Then they also designed them in articulated multi-unit sets, with permanently attached car bodies sharing trucks between them. Which shortens the overall length a bit for a 5-pack articulated set vs. 5 individual stand alone cars.

Then of course, container sizes got bigger. 20' and 40' containers are still international standards, but 45', and later 48' and then 53' containers were developed for domestic service in North America. None of these would load well onto the old single level flatcars designed specifically for 40' standard containers.

New double stack well cars were 

That's not really true exactly...  look at those photos again and you'll note that you can load:

- 2x 53' containers (or any combination really of 40'/45'/48'/53' containers) in a 53' long well

- 2x 40' containers in a 40' long well (or a well of any size really)

- 1x 40' container in the bottom of a 40' well and a 45'/48'/53' container on top, overhanging the ends of the car. In a 5-pack articulated set of 40' wells, you can alternate 53' and 40' containers in the top positions to fill up that space  like:  53/40 + 40/40 + 53/40 + 40/40 + 53/40

Here's a clear visual example, of a 53' container loaded in the top position in a 40' well:
http://canadianfreightcargallery.ca/cgi-bin/image.pl?i=dttx761243d&o=ttx

(connecting/attachment locations (on top and bottom) are standardized for compatibility with 40' standard containers, so 40/45/48/53' containers can be stacked in any combination as long as the bottom one can fit into the length of the well. 20' containers can ONLY be placed in the bottom position.)

And of course this is a very really thing as well, with different builder creating VERY visually distinctive designs that achieve the same specifications.

Intermodal cars

Intermodal cars changed designs over the years as the containers got bigger (40 ft 45 ft, 48 ft, 53 ft.).  They are also built by a dozen different manufacturers, each with their own designs.  How many different makes and models of highway trucks/tractors are a there pulling them on the highway.  Same thing.  

Different styles are designed for different service.  On the dedicated ship and long haul service, a 5 pack (5 articulated wells) make sense because its mostly a shipload of containers going to or from one dock to a single ramp on the interior.  For domestic shipments where there might be more O-D pairs, having the flexibility of 5 packs, triples and stand alone cars might be better.

An articulated well car is cheaper to build and shorter than an equivalent number of stand alone cars.

Very early container

Try this if you like the 50's.

http://www.mopac.org/store/models-and-decals/ho-scale-vehicles-trailers/item/593-custom-missouri-pacific-truck-rail-container-kit-ho

Michael H

What makes it even more fun...

... is that some of those 48' well cars were considered excess to needs, because not that many 48' containers were being shipped. The 53' container had taken over the domestic market. So they were put in storage for awhile. 

After being brought out of storage, they then had an 8' section cut out of them so the were more efficient to use with the more common 40' ISO (international) containers. 53' containers are only domestic - they don't go on the ships, at least not normally. 

Walthers has models of some of these: https://www.walthers.com/thrall-5-unit-rebuilt-40-well-car-ready-to-run-ttx-dttx-748198-a-e-yellow-black-small-red-logo-yellow-conspicuity-stripe"target="_blank"> https://www.walthers.com/thrall-5-unit-rebuilt-40-well-car-ready-to-run-ttx-dttx-748198-a-e-yellow-black-small-red-logo-yellow-conspicuity-stripe

Container weight is a factor

Some stack cars are built as "stand alones" so they can handle heavier containers.  Remember, a 20' container can weigh as much as a 53'.  Stand alones can also be drawbarred into sets, with 3-unit sets being the most common.

The articulated sets are the most common well cars and since they only have one truck between the wells the gap is shorter.  The ones designed to mainly carry 40' maritime boxes are usually 5-unit sets while those intended for 53' domestic boxes are 3-unit sets.

The single-level "spine cars" were built with weight savings in mind.  I worked in Southern Railway's intermodal department when the industry started to transition away from the 89' flats to spine cars.  There was conflict between Trailer Train and some of the railroads that owned them over how to best proceed.  TTX pushed for single-unit cars of their design (the 2-axle Front Runner) while some roads led by Santa Fe wanted multi-unit cars riding on conventional trucks.  The Southern was more on the Santa Fe's side but didn't want the 10-unit cars Santa Fe favored.  TTX went ahead with large orders for their flawed Front Runner and grudgingly started buying 5-unit articulated spine cars to placate roads like the Southern.

Around 1983 I drew up an idea for a dual-purpose spine car that had hitches for trailers and pedestals for containers.  Turns out I wasn't the only one proposing such a car.  Indeed, Atlanta's own Davidson Kennedy (a freightcar repair shop) was building a single-unit car that looked a lot like my design.  DK didn't get any orders.  They were about 6 years ahead of their time. 

What neither of us foresaw was the rise of the longer domestic container.  Our designs could only handle 40' boxes.  By the late '80s 48' and even 53' boxes and trailers were in use, and these were the death knell of the 89' pig flats and the troublesome Front Runners.  Trailer Train was forced to accept to multi-unit spine cars, now adapted to have container pedestals and retractable hitches so they could handle both trailers and containers.

As the amount of 28' "pup" trailers on the rails increased, the spine car saw a further refinement by being stretched so each unit could haul two pups or one 57' trailer.  

So there's lots of reasons for the variety of intermodal cars you see out there.  I could go on and on and on.....

Scott Chatfield

container cars

ok so not really a weight cap reason. just the way a manf decided to build them.

yes i understand the length of each can. and that most cars are built low for double stacking. and they put the 48-53 on top of a 40 foot can. never seen the bottom as two twenty footers. only a forty on top of two short boxes. or maybe i just missed them.

so the reason of so many styles of cars, is just a manf deal. good as i did not want to start using said cars in the wrong way.

have seen many a spine car with a can on it. even a trailer in a low belly car  (it looks funny).

i would have to modify my spine cars to fit a can on them.

i do not do much container trains. as my home layout is small. seeing as only a couple cars can be longer than my longest yard track. but i do have a bunch of them in deferent styles, including some that are no longer used.

48' rebuilds

Technically most rebuilds had two 4' sections cut out from each end. If you cut it out of the middle you have to rebuild all of the bracing structure and relocate all the container mounts.

Some were also extended to 53' by adding length at each end.

never seen the bottom as two

http://canadianfreightcargallery.ca/cgi-bin/image.pl?i=dttx748139b&o=ttx 53/2x20

http://canadianfreightcargallery.ca/cgi-bin/image.pl?i=dttx748281b&o=ttx 2x20 single level

http://canadianfreightcargallery.ca/cgi-bin/image.pl?i=dttx748860a&o=ttx 40/2x20

A few well cars out there are "all purpose". You can't just load a trailer into any well car. All purpose cars have a "bottom" that will support the trailer's wheels and hitches on the end platforms of the car for securement. Container-only wells (more common) generally just have open cross-bracing in the bottom of the car.

Intermodal Reference Info

Here's a decent container reference I came across a while ago.  The container info starts at Page 50.

http://www.tracintermodal.com/wp-content/uploads/PDFs/Introduction%20to%20Intermodal%20Industry%20-%20TRAC.pdf

Another website with a brief summary and other info:

http://www.matts-place.com/intermodal/part1/modelerseras.html

If you are interested in the intermodal history, I'd suggested two books:

"Piggyback and Containers, A History of Rail Intermodal on America's Steel Highway" by David J. DeBoer and/or "Intermodal Railroading" by Brian Soloman.  DeBoer's is a good history lesson.

yes i have seen photos number

yes i have seen photos number two and three. as to the first one. only goes to prove i had just not seen them. but then most of my train watching these days ( past number of years) has been from the seat of a moving commercial truck. so can not really look closely at much of anything but traffic and road.

do they stack on top of the 20 ft tank containers?

do they stack on top of the

No, and the outlet valve must face the car end.

oops, ment on top. as two

oops, ment on top. as two twenty footers on the second level.

yes i know can not load them on-top of a forty footer.

Just found this subject

Just found this subject thread. I can see I need to do a lot more reading to try and understand some of this considerable subject. Two questions I have most immediately is about our unloaded MODELcontainer cars. Are they underweight to the point of not operating well in a string of 10 or more cars?
 

Here are several questions I posted on other subject threads, but have not had answered yet.

1)  Metal Frames or added weights?

A little extreme perhaps...

A little extreme perhaps...

I replaced the floors of my Walthers Thrall cars with laser cut steel floors. The model originally came with steel weights that mounted underneath the plastic floor but they prevent you from seeing the track beneath the car, which is noticeable if you're running the cars empty. So I drew a new floor in CAD using the plastic floor as a template, then cut the plastic floor out and installed the metal floor. It isn't as heavy as the car was with the solid metal weight, but it's much better than just the plastic floor.

The new metal floor is actually two layers of steel. The openings are slightly larger on the bottom layer which helps give the impression from above that the floor is thinner than it actually is.

I have not had the opportunity to operate these cars on anything but the test track since I added the metal floors but they seem to perform fine. I know others who never installed the solid metal weights in theirs and could handle them without incident so adding weight should not have a negative effect.

Cut Out Stock Metal Floor?

Nice looking job Ryan.

I wonder if someone could just cut out portions of the metal plate that came with those cars?

Or use the sheet form of lead that plumbers/roofers use to use?

Tried both, not effective

I tried both, but cutting the steel floor was an exercise in futility. I just don't have the tools to do it.

A few years later I tried cutting lead sheet, but my cuts weren't very crisp and it was very labor intensive. Since I was dealing with lead I didn't want to file, grind or sand the metal so it really limited what I could do to make precise cuts.

When a friend recommended the vendor he had used for a laser-cut project I looked into it and was shocked at how low the cost was. I figured it would be much more than the cost of the car but if I remember correctly it was right around $35 to do the entire 5-unit car.

Could those laser cutters cut

Could those laser cutters cut the stock metal sheet,...or the lead? Isn't that what you did is have a laser cutter cut those metal sheets you utilized??

The company I used offers

The company I used offers several materials in different thicknesses. I just went with what I thought would work best. Supplying the metal myself wasn't an option. Besides, I wanted to use two layers to create the illusion the material was thinner than it actually is. The two layers cost $3.52 and $3.27 to do one platform (5 of these for a 5-unit articulated car). Those are 0.030" thick stainless steel.

I might try 0.030" for the top layer and 0.060" for the bottom layer next time to gain more weight. I have some other parts I need cut in 0.060" stainless and they have a minimum $30 order for each thickness so that would help me fill out the minimum order.

@Ryan

I really appreciate your continued interest and answering my questions about your 'weighting' experiments. I'm going to have to get a full inventory on the misc cars I purchased over the years, and see which ones are viable for my operation,....and then which ones I might need to modify to run unloaded.

I do recall that I purchased a couple of spine car sets that had been very carefully set up by a fellow who liked doing them. And as I understood at the time it was quite the challenge to make them run very consistently. He promised I would be very pleased.

I also recall having bought several sets of brand new 'twin stacks'. Folks are charging a lot for these currently,...glad I bought them when I did.

Right about the Twin Stacks.

Right about the Twin Stacks. I have a kit to build, but I would like to buy an RTR to see how it's done somewhat. Intermountain could just make it easy on us and run these again!

As far as the spine car sets are concerned, especially the Athearn Impack cars, I took Joe Fugate's advice and used four tiny washers (18-8, #0 hole size 0.063" ID, 0.016" thick) on each axle end of Intermountain 28" wheels inserted in the car's trucks. Before inserting the washers the cars would lean to one side or the other but now that's gone. It took some time to install 16 washers per truck over 11 trucks on the 10-unit car but it was worth the effort. The cars are steady now and do not lean one way or the other. I can't imagine those tiny washers added much weight, but the cars are light enough every bit helps I suppose.

53 on top of 40, in 40 well car

I was just going to ask this question on the forum about 40' rebuilt well cars, when I ran across this quote excerpt. I suppose this could not be done with 2 adjacent cars?

I had also run across this walthers listing...
https://www.whiterosehobbies.com/products/walthers-mainline-910-55605-ho-scale-5-unit-rebuilt-40-well-car-bnsf-238144

PS: Then another question,...perhaps this can be done on prototype railroads, BUT can it be done on our 'tighter radius' model railroads??

48' well cars

And I suppose if this particular double stacking can be done on 40' well cars, it can be done on those 48' well cars,...which I have a few of already?

40/48

Attachment points are standardized for 20' and 40' containers.

It's possible some cars might not have central attachment points for securing 20' containers, but ALL cars will handle 40' container.