Trains remain one of the most popular forms of large-scale transportation more than 200 years after the first steam-powered engine pulled a load of cars down a railroad track. Much of that longevity is rooted in the fact that trains can carry a lot of cargo and passengers at a relatively low cost. Yet making a reliable train is not as easy as it sounds.
Engineers putting together a new train design must rethink every part of previous designs and look for ways to improve on them. In the era of high-speed rail, one of the things that they have to look at is the ballistic properties of those materials they intend to use for body construction.
The ballistic properties of a given material relate to that material’s ability to withstand strong impacts at high speeds. Just as a projectile fired from a handgun can travel at amazingly high speeds, so can high-speed trains. The impact they make with airborne debris can be as devastating as the impact of a bullet on materials not strong enough to withstand it.
Testing Ballistic Properties
So, how do train designers test the ballistic properties of the materials they are working with? By firing projectiles at them. They set up experiments that simulate the impact that might occur in a real-world setting. Then they see how the material in question responds.
Any material not strong enough to withstand ballistic testing is not suitable as a body material for high-speed trains. Body materials have to be able to withstand impacts at high speed, otherwise a train could be compromised at any point during its journey. Everything from windshield glass to nose panels has to be tough enough to pass the tests.
Without materials tough enough to withstand ballistic testing, there would be no high-speed trains. Either that or rail companies would constantly be taking their trains out of service in order to repair impact damage. To avoid that, Rock West Composites says designers look to tough composites like carbon and glass fiber.
Glass Fiber’s Ballistic Properties
Russian scientists at South Ural State University have been working on developing a glass fiber reinforced plastic (GFRP) tough enough to withstand the high impacts modern trains are subject to. Glass fiber was chosen because, like carbon fiber, it is many times stronger than steel yet lightweight and resistant to a full range of environmental conditions.
When they began working on the project, the scientists were not quite sure how glass fiber would handle ballistic testing. It turns out they had nothing to worry about. Their GFRP is more than capable of handling the impacts associated with high-speed rail. But it gets better.
In order to test the GFRP, the researchers subjected it to a variety of conditions simulating different loads. They tested it in its natural state. They stretched it and tested it again. They even created preloaded plates of simulated fine elements and exposed them to ballistic impact as well. In short, they twisted and turned the GFRP in every possible way to determine how well it can handle various loads.
The tests turned out so successful that scientists think the material will be usable across an entire train body rather than just the nose. It handles light and heavy loads equally well, at both low and high speeds.
Carbon fiber is the composite of choice among aerospace and maritime manufacturers. It is also well received among train designers. But it looks like glass fiber might give carbon fiber run for its money in the train department. It will be interesting to see what happens.