The Powercab ( 5240025) is a complete system including power supply. You will need to have a method to connect to the track with two wires. The connection panel has an included removable plug with two screws for the ends of the wire coming from the tracks.
Since the Powercab only has a single track output, (two wire) that same output does double duty for programming. When you put the Powercab in “program track” mode, that same output now becomes your program track. So this means you entire layout is now a programming track!
Do not confuse this with OPS mode programming (POM) programming on the main. POM begins by selecting the loco you wish to modify first. Thereby eliminating the possibility of programming multiple locos at once UNLESS you have multiple locos set to the same address such as 3.
If you want a dedicated programming track to use with you Powercab we have the AutoSW for that purpose.
The AutoSW is a smart relay board with one input (two wires from powercab output) and two outputs. One output for the main layout and a second output for a programming track.