I assume you are talking about the Circuitron 'Track Power Adapters'? They basically have two leads for input, and two output leads with a fixed voltage. Diagrams/pictures are available on the Circuitron web site:
http://www.circuitron.com/index_files/301CAT.pdf
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin
Has anyone installed
how does it work is it hard to install?