See TRUE AND TREMBLING BRAKEMAN The DT version leaves out the first verse, which goes:

See the true and trembling brakeman
As he signals to the cab;
There is only one thing for it
And the train it is to grab.

See also CHATTANOOGA CHOO CHOO, And other songs with links collected HERE I think Suzanne is thinking of ENGINE 143 a.k.a. THE WRECK ON THE C & O (Carter family). These should help for a while.