Two weeks ao I stayed with a friend in New York City. While there I rode the Eigth Avenue IND Line (A, C, E) Trains many times and noticed all the cars had their roller bearing partialy painted. The paint was applyed to 1 half of the bearing. Any reason for this?
I don’t know about NYC subways, but I’ve seen a lot of new unit coal cars with the bearings painted blue and I’d guess it’s some kind of temperature sensing paint that changes color if the bearing gets too hot. Can anyone confirm this?
I’ve seen some applications with trucks and trailers where some of the wheel is painted in order to easily tell if the wheel is moving or if it is just sliding along (brakes stuck on).
Something similar to this, maybe?