@article {Beaman:2006-12-01T00:00:00:0025-570X:347,
author = "Beaman, James D. and Beyerstedt, Erin J. and Snavely, Mark R.",
title = "Counting Train Track Layouts",
journal = "Mathematics Magazine",
volume = "79",
number = "5",
year = "2006-12-01T00:00:00",
abstract = "Train track layouts with switches not only provide children with hours of amusement, they provide us with a number of interesting mathematical problems. How many different layouts can be made from a set of track with two switches? What do we mean by *different*? We develop two different but reasonable definitions for equivalence of train track layouts, and in each case, count the number of equivalence classes. We use such tools as two-term recurrences, directed graphs, and eigenvalues of incidence matrices to learn about the fascinating mathematics of train track layouts.",
pages = "347-359",
url = "http://www.ingentaconnect.com/content/maa/mm/2006/00000079/00000005/art00004"
}