About track circuit

[oxfordjack]

Where I can referrences for the below question?

how track circuit affects the design nof traction current supply and return?

Thank you.

[PJW]

Where I can referrences for the below question?

how track circuit affects the design of traction current supply and return?
Thank you.

The IRSE test book "Railway Signalling" and the relevant small green book on track circuits would be a good start. Search for terms such as "negative bonging, impedance bonds, return conductor, booster transformers, isolation sections, double-rail, single-rail, immunity" etc