Full disclosure I know less than nothing about fabricating so if the following are stupid questions I apologize.

My wife and I have for many years toured on a old linear recumbent tandem. It has died. On a number of occasions we have been thrown off or been denied passage on trains because the bike was too big to fit in the bike car. What is required is a tandem that breaks down EASILY. From an ease of breakdown standpoint the major problem seems to be related to the chain. If one was to use a front wheel drive system say from cruzbike or similar and couple it to the rear portion of any decent tandem it seems to me this would solve many of the breakdown issues.

Am I missing something here?

I know this is not a perfect solution as one now has 2 unicycles and gear to lug through a train station so if anyone has better suggestions please please please let me know.

thank you for your thoughts
K

Are you proposing separate drive systems front and back? I suppose that would work.
If all you want to do is break the bike in half, it seems like S&S couplings in the middle would do the job. Do you have any pictures of the dead bike

Exactly. Two drive systems, which would have the (albeit small) advantage of independent gearing for each party. I am hoping that S&S couplings are available for the size of tubing on has to have for a recumbent tandem.

Have you looked at the Ritchey breakaway tandem? There are others out there that also make breakaway tandems but the price goes way up.

https://mtbtandems.com/product/ritcheybreakaway/

https://curtlo.com/portfolio-items/breakaway-tandem/

Seems it would be a lot cheaper/easier to buy a production frame than design/built a new concept frame.

I looked at images for recumbent tandems. Turns out someone made a tandem like what you are proposing. Search for cruzbike tandem. I'm not really sure it helps you, the back half is huge.

Seems to me that you can easily remove the timing chain and split a recumbent tandem without much issue. S&S makes some pretty big couplers, but if you really need a bigger keel beam, you can go with two tubes.

On edit: I asked someone that knows a lot more about 'bents than I do, and it turns out I should have looked on the S&S site. This one would work pretty well with a cruzbike front end. You could split it in front of the rear crank and behind the captain's seat. Barcroft Columbia Tandem Recumbent with S and S Couplings

Thanks for the input. Wsteve464 I should have specified it has to be a recumbent because my wife cannot tolerate any wight on her wrists. The barcroft looks interesting I will check it out. I would very much prefer to buy something pre-made The issue with a bent such as the barcroft is dealing with the chain when one has to break it down to get on a train. When we are touring we are carting around 40 pounds of gear hung from every possible point on the bike. Getting all that off, breaking down the bike and then lugging it all onto a train is not a job for the faint of heart. When you are catching a train in some little town you've got about 2 minutes to get everything on. Sometimes the train people are helpful and sometimes they are not.
Thank you very much for your thoughts. I really appreciate you taking the time to help me on this quest.

For some reason the site keeps asking me to reload because the token has expired, so if there are 5 copies of this I apologize

When you log in, are you selecting "remember me"?

I don't think you are going to find anything premade, but let us know if you do. Although you might have to have couplers added