Ask Trains: Why don’t western railroads straighten out their main lines?

Question: In many photos taken on open land in the West and Midwest, you can see curvature in the tracks even though there are no visible obstacles such as rock cuts, rivers, or buildings that would prevent the alignment of the railroad from following a straight path. Why would today’s managers not consider realigning the tracks to straighten the route? — Andy Kirk, Jacksonville, Fla.

Answer: The initial route of a rail line is a compromise between cost, grade, and curvature. Early railroads were often built as cheaply as possible and improved when traffic and profits justified the cost. That’s when the old alignment can be abandoned in favor of the new, like parts of the Union Pacific’s original Transcontinental route, or kept in service.

Michael E. McGinley, a senior track engineer at Advanced Rail Management Corp., says that given a freight train speed of 70 mph, curves less than 2 degrees (about a 3,000 foot radius) do not slow trains nor increase rail wear compared with straight track. He added that grades often limit a train’s speed more than curves. This leads right back to the cost-benefit analysis.

McGinley says that passenger services change the business case for faster track, since increasing speeds to reduce travel time is more important than cost savings on operations and maintenance. — Tyler Trahan, a Trains contributor