On The Atchison Topeka And The Santa Fe in A#

On The Atchison Topeka And The Santa Fe in A#

Key of A#

A# (Bb) major requires barre chords rooted at fret 1 on the A string or fret 6 on the E string. Despite the barre demands, it is a common key in funk, New Orleans R&B, and brass band music. The open D string can ring as the major third for added color. A# is a intermediate-level key on guitar because the open D string is the major 3rd of Bb, adding a bright color if allowed to ring. Expect to rely on barre chords throughout, which builds hand strength and unlocks the entire fretboard.

Voice Leading

The bass line moves through A# to F (descending perfect fourth), F to F (ascending unison), F to A# (ascending perfect fourth), A# to G (descending minor third), G to F# (descending half step), F# to A (ascending minor third), A to C (ascending minor third), C to C# (ascending half step), C# to F# (ascending perfect fourth), F# to A# (ascending major third), A# to F (descending perfect fourth), F to D# (descending whole step), D# to A# (descending perfect fourth), A# to A# (ascending unison), A# to D# (ascending perfect fourth), D# to D# (ascending unison). A half-step bass movement creates a strong leading-tone pull that demands resolution. The root motion by larger intervals (fourths and fifths) gives each chord change a strong, decisive character. When the progression loops, the bass returns from D# to A# by perfect fourth.

Scales for Improvisation

A# major pentatonic works because every note is either a chord tone or a safe passing tone — there are no avoid notes. For soloing, this means you can play freely without clashing. Over dominant seventh chords, A# Mixolydian adds the flat seventh for an authentic blues-rock edge.