I've Been Working on the __, All the Livelong Day

This page is the CodyCross answer for the clue below from Mexico, Group 1375, Puzzle 5 (Marietas Islands).

Question is: I've Been Working on the __, All the Livelong Day

and the answer is: RAILROAD

Word Meaning:

RAILROAD — (chiefly US, Philippines) A permanent track consisting of fixed metal rails to drive trains or similar motorized vehicles on.

Definitions from Wiktionary.

I've been working on the __, all the livelong day — CodyCross Answer | CodyCross Solutions