Compared to honey combs, whiskers, stacks, or wallet fades, train tracks are a more uncommon fade that occurs along the outseams of the jeans. As the denim wears, the outlines of the selvedge will be become more apparent, forming two sets of lines that resemble train tracks running up either leg.
As the outseams do not undergo as much stress and wear as other areas of denim, it is difficult to achieve this particular fade. Like anything, however, it is not impossible. To facilitate train tracks fades, consider flattening the outseam before you start wearing it.
Often times, the selvedge outseam gets folded in two, producing a one-sided train track. From my experience, I didn’t really think about flattening the selvedge before wearing it, so my current N&F jeans have one-sided train tracks on certain areas and two-sided train tracks on other areas.
How should one remedy this problem? It’s simple – iron the selvedge from the start!
Roy ironing the selvedge (fast forward to 2:08):
Train Track Snapshots (source: superfuture.com)
Even non-selvedge jeans can get train tracks. The fading comes from two sides of pressing on the outseam of the jeans to cause indigo loss. Though you’ll have better stronger contrasting results with selvedge raw denim, it is still attainable with non-selvedge.