I've been working on the railroad..

                   all the live long day....

This is one of four trailer twist locks that a container sits on. Those 4 locks are what keeps the trailer attached to chassis..  When picking trailers in the rail yard part of our job is to lock down the trailer. Two locks are supposed to be "automatic" but the older the trailer the more likely it has failed.. I also learned how to swap chassis when one isn't safe to be on the road.. All part of the routine pretrip.. 

On the way home from work this was on the radio.. A great way to end the day..