I have an Atlantis pool and I am looking for is top rail connector part number 3474
That is an Asahi top cap. Unfortunately, we do not carry parts for that brand. We recommend trying https://www.asahiparts.com/
Looks like this
Hi, Could you please take a look at this link Atlantis Top Connector and let us know if this looks like the part you need. Also please compare against these Atlantis Top Connector Dimensions.