Just mention Colorado to the avid rail fan and you have their interest; add the term 'narrow gauge' and you have their undivided attention. Why this special interest in the Centennial State's railroads which span 120 years? One reason is Colorado's geography -- relatively flat plains in the eastern third of the state, the rugged Rocky Mountains in the central and southwest areas. Colorado's railroads traverse all these regions -- from a 2285 foot elevation to the heights of 14,000 foot peaks. This geographical configuration makes Colorado railroading second to none.