I learned the song in the late 1950's, probably from my father (who still sings it) or at a YMCA day camp in upstate New York. I vaguely remember that there were slight differences between those versions, but can't pinpoint them. The lyrics that are ingrained in my memory are sufficiently mutated from those previously posted that I thought it worth offering them:

Chorus:
Patsy-o-ree-i-ree-ay,
Patsy-o-ree-i-ree-ay,
Patsy-o-ree-i-ree-ay,
A workin' on the railway.

In eighteen hundred and forty-one,
The railway line had just begun, (3x)
A workin' on the railway.

In eighteen hundred and forty-two,
Found myself with nothing to do, (3x)
A workin' on the railway.

In eighteen hundred and forty-three,
The section boss was driving me, (3x)
A workin' on the railway.

In eighteen hundred and forty-four,
My feet were tired and my back was sore, (3x)
A workin' on the railway.

In eighteen hundred and forty-five,
Found myself more dead than alive, (3x)
A workin' on the railway.

In eighteen hundred and forty-six,
Stepped on a couple of dynamite sticks, (3x)
A workin' on the railway.

In eighteen hundred and forty-seven,
Found myself on the way to heaven, (3x)
A workin' on the railway.

In eighteen hundred and forty-eight,
Picked the lock on the Pearly Gate, (3x)
A workin' on the railway.

In eighteen hundred and forty-nine,
Found myself on Cloud Nine, (3x)
A workin' on the railway.

In eighteen hundred and forty-ten,
Like my story I'll tell it again, (3x)
A workin' on the railway.