Who builds light weight commuter trains?

Question

Airplanes moved from Aluminum to composite plastics that are stronger than steel, on a per pound basis. But, I couldn't find a train that uses this weight saving method. Perhaps, there are none?

Answer 1

Aircraft and rail are different applications.  In air, weight is everything and justifies the expense and difficulty of working with those materials.  After all, aluminum is vulnerable to corrosion, and is brittle and must constantly be inspected for fatigue.  When composites take damage, they tend to delaminate or shatter.

For railways, weight is not nearly as much of an issue.  So the winner is stainless steel - strong, highly resistant to corrosion and fatigue, and can easily be prepared by welding.  Stainless steel car bodies from the 1940s are still virtually as good as new.  Barring wrecks, they're indestructible.

Answer 2

In the U.S., commuter trains that share tracks with freight trains do need to satisfy FRA collision safety regulations, so they do need to be built rather sturdily.

Lately the newer commuter cars being purchased by various transportation authorities around the U.S. seem to be coming from a couple of manufacturers such as Bombardier and Kawasaki.  For instance, new Bombardier M-7s are being phased into service right now by the huge commuter rail networks in the NYC area (Metro North and Long Island Railroad)..

Answer 3

Japan.

Answer 4

In Canada it's Bombardier. Light rail/subway trains for parts of the world.