Counting On The Tracks

There's a brunette walking down a set of railroad tracks saying:

- 21, 21, 21...

Then a blonde pulls up, gets out of her car, and says:

- What are you doing?

The brunette replies:

- Just counting.

The blonde says:

- May I join you?

- Yes, - replies the brunette.

So the blonde and the brunette are now both walking down the railroad tracks saying:

- 21, 21, 21...

A train comes and the brunette jumps off the tracks as the blonde gets hit. After the train passes, the brunette gets back on the tracks and says:

- 22, 22, 22...