Now cantilever brakes on a tandem, that's another story. Terrible stopping power but still, not even close to a "did not die" situation. More like a "we need to get rid of this ****" !!!!
My Tandem came with the self energizing cantilever brakes. rain, shine or snow they worked well. Once they were wore out. They were no longer available for sale. I found some Magura hs66 brakes at Cambria 18 years ago. They were new old stock. I had tried other cantilevers and they sucked compared to the self energizing brakes. The Magura rim brakes were and still are the best brakes I have ever owned.