single

one train engine

One train engine going DOWN the track

Chug, chug, chug, chug, clickety, clickety, clack

One train engine going UP the track

Chug, chug, chug, chug, clickety, clickety, clack

TOOT!  TOOT!

[You can find this rhyme in The Eensy Weensy Book of Little Fingerplays]