What does "That’s a hundred and four with the Acela Express." mean in English for Spanish?

In English for Spanish, "That’s a hundred and four with the Acela Express." means:

Son ciento cuatro con el Acela Express.

Listen to "That’s a hundred and four with the Acela Express.": (If you have an HTML5 enabled browser, you can listen to the native audio below)

This is a phrase that is used in the GamesForLanguage English for Spanish Language Game in the following scenes:

• English for Spanish 3, Level 3, Scene 7