A simple tune played in the Key of B (but using the chords for the key of G)

CAPO 4.  The intro is a lot of harmonica...play what you see fit.

G (320003@1)                           C (x32010@1)    GOnce (320003@1)upon a time there was an engineer, 
G (320003@1)                         A7 (x02020@1)    D7who (xx0212@1)drove a locomotive both far and near, 
G (320003@1)                               CAccompanied (x32010@1)by a monkey who would sit on a stool,
G (320003@1)             A7 (x02020@1)       D7 (xx0212@1)         Gwatching (320003@1)everything the engineer would pull.

G (320003@1)                           C (x32010@1)     GOne (320003@1)day the engineer wanted a bite to eat,
G (320003@1)                                A7 (x02020@1)     D7He (xx0212@1)left the monkey sitting in the driver's seat,
G (320003@1)                                     CThe (x32010@1)monkey pulled the throttle the locomotive jumped the gun,
       G (320003@1)         A7 (x02020@1)          D7 (xx0212@1)      Gand (320003@1)at 90 miles an hour down the main line run.

Chorus:
G (320003@1)                   C (x32010@1)      GThe (320003@1)big locomotive is right on time,
G (320003@1)                       A7 (x02020@1)     D7the (xx0212@1)big locomotive coming down the line,
G (320003@1)                       CThe (x32010@1)big locomotive number 99,
G (320003@1)        A7 (x02020@1)          D7 (xx0212@1)    Gleft (320003@1)the engineer with a worried mind.

The engineer got the dispatcher on the phone,
he told him all about his locomotive was gone,
he said get on the wire switch operator to right,
cause' the monkeys got the main line sewn up tight.

The switch operator got the message in time,
Said there's a north bound living on the same main line,
Open up the switch we gonna let him on through,
cause the monkey's got the locomotive under control.

REPEAT CHORUS

It is the same progression throughout the song. 
 Improvise and have fun with solos, repeats, etc.   
A great and simple fun campfire song.