Using Lipschitz distance on Outer space we give another proof of the train track theorem.
@article{bwmeta1.element.bwnjournal-article-doi-10_4064-fm214-1-1, author = {Mladen Bestvina}, title = {A Bers-like proof of the existence of train tracks for free group automorphisms}, journal = {Fundamenta Mathematicae}, volume = {215}, year = {2011}, pages = {1-12}, zbl = {1248.20025}, language = {en}, url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-fm214-1-1} }
Mladen Bestvina. A Bers-like proof of the existence of train tracks for free group automorphisms. Fundamenta Mathematicae, Tome 215 (2011) pp. 1-12. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-fm214-1-1/