Marx #666 train set restoration

[trainsnwine]

I am in the process of bringing my old Marx train set back to life.   The wires connecting the transformer to the track have been lost and so I need to replace them.   The transformer is a 50 watt; Cat. #1209.  The locomotive is pulling 4 cars around a track that is currently about 10 feet in length.   I would like to add another 5' of track.   What kind of wire is optimal for my configuration?   Thanks.

[overall]

For just one train, some # 14 or #18 stranded copper ought to be gracious plenty. Visit your local Radio Shack and ask the clerk for hook up wire. It comes on a little reel inside a plastic package.

George