SwimIn2012
It's a dumb idea. If you want the track hidden, it goes under the coping which cantilevers more than standard over the pool edge. Need a box for the cover to retract into and the bond beam is 2" below the beam where the cover enters the box. Need a drain from the box as well as electric. This assumes if you want the track hidden, you also want the box hidden when the cover is retracted.
You need to build it now or resign yourself to having an above ground box and track. Good luck.

Bummer. Thanks for answering.

I'm looking into retrofitting a pool with a pool cover with built in under-coping track. We would have to remove the coping, then dig a little for the track, which they said won't require any additional cantilevered coping, plus we have to dig a 14" wide by about 18" deep (I think) trench for the motor. However I just met with the pool cover people today and still have to see what the contractors say about the cost of demolition, trenching, tile work, etc. to make this all work. If it's too expensive, the pool cover is going on top.

If you can find a pool cover contractor who is willing to put in the track now and the motor and pool cover later, that would be ideal. If it's not too late, that is.

David