3 ms·

My weird idea would be if sound waves would travel differently down the rail dependent on temperature. Although, the rail is likely not uniform enough to detect

My weird idea would be if sound waves would travel differently down the rail dependent on temperature. Although, the rail is likely not uniform enough to detect the differences? I found a device that is in use - Verse[1]. It claims to be able to measure the neutral? Although my read says the rail must be below neutral, and therefore under tension, to determine what the neutral is? They unclip the rail and then lift it with a known force? I guess that lets them measure the tension and lateral forces on the rail? [1] https://www.pandrol.com/us/product/verse-rail-stress-management/ https://www.pandrol.com/us/product/verse-rail-stress-managem... https://www.youtube.com/watch?v=Qg9vn50ZOdo https://www.youtube.com/watch?v=Qg9vn50ZOdo https://www.youtube.com/watch?v=WbNzhMsUOwA https://www.youtube.com/watch?v=WbNzhMsUOwA Railway buckling video: https://www.youtube.com/watch?v=jJeiYaSFCf0 https://www.youtube.com/watch?v=jJeiYaSFCf0 Verse PDF: https://railway-news.com/wp-content/uploads/2020/02/VERSE-Technical-Information-Pack.pdf https://railway-news.com/wp-content/uploads/2020/02/VERSE-Te...

salty_biscuits 4y ago
That's interesting. Unclipping the rail is a bit of an exercise though. Makes sense that it must be in tension, otherwise it would move on unclipping. I guess they just measure it in the morning. All these types of devices are less practical as soon as you have to disrupt services to do the measurement. Your idea of the measuring the dynamic response is something that has been investigated. Modal testing is very common (using accelerometers on the rail and a force measuring hammer). The effect would depend on the boundary conditions of the rail (so basically something that varies from site to site) so you would need to track how it changes over time. The engineering problem is how to collect this data easily.

salty_biscuits 4y ago

That's interesting. Unclipping the rail is a bit of an exercise though. Makes sense that it must be in tension, otherwise it would move on unclipping. I guess they just measure it in the morning. All these types of devices are less practical as soon as you have to disrupt services to do the measurement. Your idea of the measuring the dynamic response is something that has been investigated. Modal testing is very common (using accelerometers on the rail and a force measuring hammer). The effect would depend on the boundary conditions of the rail (so basically something that varies from site to site) so you would need to track how it changes over time. The engineering problem is how to collect this data easily.