Clanking sound on Amtrak's P42's

[David Collins]

https://www.youtube.com/watch?v=YaCMCHDKwQo

At timestamp 6:23, the leader on Amtrak's westbound capitol limited hits the switchfrog at CP 421 in Elkhart, Indiana which makes a clanking noise, I've heard it only on Amtrak's Genesis engines (P32's, P40's and P42's) but don't know what creates it, is it the flanges making that noise or something else? it sounds pretty cool though.

[Saturnalia]

Sounds just like something in the truck suspension. All equipment will sound slightly different depending on the trucks, and those are high-speed dampened trucks. Most Amtrak equipment makes a similar clank so I’m guessing it’s the damper.