Replacing the power cord is very simple to do. Here are the service manual pages for the 1043 transformer. http://pictures.olsenstoy.com/searchcd31.htm?itm=646 Study it before proceeding so that you are familiar with the insides and what to expect. Also familiarize yourself with the terms that are used to describe parts. This helps in future communications.
Take out the 4 screws in the top, and remove the cover. Look at how the wire is routed to the transformer, and unsolder the wires on the coil. You will need a heavy duty soldering iron, or better, a soldering gun. Put a knot in the new wire to act as a strain relief, and solder the new wire in identically like the original. It does not matter which wire goes where on the transformer coil. Replace the cover, making sure to line up the controller arm with the contact arm. Screw the cover in place, plug in the transformer, and test it by hooking it to your track and running trains. Suggest taking photos of the transformer during dis-assembly, so you can refer to them when reassembling it.
Non-polarized power cords are available online at most parts dealers.

A happy thanksgiving to you, and everyone else.

Enjoy your trains!

Larry