You would need FasTrack to Tubular track conversion pieces to use with FasTrack. It's a decent bridge albeit slightly noisy, but smooth operation.
Dave's point is well taken. To use the 6-14173 with FasTrack you will need the adapters from traditional tubular to FasTrack because this bridge uses traditional tubular.
Furthermore, search results from several search engines seem to indicate that there is no FasTrack version of this bridge, i.e. none was ever offered by Lionel, so employing the non-FasTrack version with adapters are apparently the only way to go.
Mike