Electra Townie 3i replacement chain?
 

Where to find a replacement chain for Townie 3i ?

It appears to be a single speed with coaster brake, so any SS chain should work. Go to a Trek dealer or spend less at Amazon, Universal Cycle or many other places. I would purchase a Shimano, SRAM or KMC though. BTW, you'll need a chain tool to "cut" the chain (I would use the same number of links as the stock one), and need a chain tool (go to SheldonBrown.com if you're unsure how to do it).

Thank you. I now think it is not the chain but the hub, some skipping going on at shift change in 2 of the speeds. Pondering what to do. Downloaded the Shimano Nexus manual.
On the other hand I successfully made some changes to a recently purchased Electra Cruiser 1, new handlebars and a hand brake, and am happy with her. Maybe 1 bike is enough.

Skipping implies a shift cable adjustment issue. On a single chainring / single sprocket setup like the Townie 3, there shouldn't be any chain issues unless the chainring is bent or chain links are damaged or worn badly.

Edit: It could also be the internal gearing failing in the 3-speed hub. My wife's Townie came with a 3-speed hub. I replaced it with a custom-built wheelset with a 7-speed hub, and used the original wheels on another bike, and in a few years or less than 1000 miles the original 3 speed hub seized and failed, despite ample original lubrication.

Here you go:

Thank you so much for finding that for me!

It appears that the shifting issue has been amply addressed. But regarding a chain for these, you may have to combine 2 chains to have a long enough chain.

No, it wouldn't need 2 chains to make this work. If you have a stable of 40 bikes you should know that the 3i stands for "internal gear". It's a 3 speed Shimano Nexus, and uses a single, single speed chain. That's why a posted a video on how to adjust it.