Ted,
I never sang in a chorus (can’t carry a tune) so let me say before you send it back check with the dealer first. In the age of BTO dealers do not stock engines like they used to. Many of the big dealers only buy one or two extra engines most are purchased by the dealer for pre-orders so you dealer may not have a replacement engine. To glue on the phone antennas use any clear super glue to reattach the posts. I being a Pennsylvania fan have several engines, RS11, GP9, E8, F7 all with antennas and have broken a few by handling but never had one arrive broken. Maybe luck but Lionel IMO does a good job protecting the antennas with inserts to hold the antennas safe while shipping.
As far as getting to you Legacy controls the section of the roof behind the cab with the fan on top lifts off. Place your fingers behind the fab and firmly lift up. Be careful of the antennas that is how I broke most of the ones I had to re-glue back. Also do a search for other posts about the Train Master engines Lionel just release how to get to the Legacy control switches for reference (just go down this forums page to find). Good luck
JohnB
