I'll acknowledge KPL, for the "tune down 1/2 step" being right.  You even had the right
but all in the wrong order.  Also, all the sites I saw didn't have the lyrics written
way I hear them on the Thin Lizzy 'Live and Dangerous' (1978) album.  You obviously 
play your chords to see if they worked right.  Here's my correct transcription of a great song:

I use major bar chords throughout, except for the F#m.

Southbound  -Thin Lizzy  (1/2 step down to sound like recording)

Intro: [ A... B C#...  /  B... C#
C# B A ] x2

A...              BC#... (x2444x@1)The boom time it is over
B...              C# (x43121@1)name="chord_xx0232@1">D
A ghost town is all that's left here
A...              BC#... (x2444x@1)The gold rush it is over
B...              C# D...E  (rhythm guitar go to 7th fret bar E chord)
And depression days draw near

So tonight after sundown
I'm going to pack my case
I leave without a sound
Disappear without a trace

A...F#m...        D...      B (x2444x@1)name="chord_022100@1">E
Ohh-hh, I'm going southbound    (x2)



Drifting like a drover
Chasing my career
From the ships docked in the harbor
New horizons will appear

Tumbling with the tumbleweed
Down the open road
Taking only what I need
Before my head explodes

Ohh-hh, I'm going southbound (x2)


Hey, you're not gettin' any younger
The wild west has already been won
Northern nights are growing colder
And the old Eastern ways are gone

So tonight after sundown
I'm gonna pack my case
without a word, without a sound
disappear without a trace

Ohh-hh, I'm going Southbound

A...          F#m...
New horizons will appear
D...          E...                 (repeat 4 chord figure here)
Oh, I go to South of here
without a word, withound a sound
I got to leave this ghost town
Ohhh-hh-hh...,
let's go down to Rio
I got to go, oh you know
D...            B (x2444x@1)EI'm (022100@1)Southbound.  Southbound!

Outro: