With a cherry picker basket and lift, used to repair electric lines.
What are the braided wires hanging on racks on the back that look like foot long hair pins?
I’ve wondered the same thing. I’ll tell you my guess so far (and bump the thread) but i don’t really know. I think they’re probably for grounding purposes. For one thing they could be used to attach between the bucket and ground to keep that at ground potential. Another use would be to tie the different phases together after the circuit is opened. That way, if the line is accidentally energized the phases will be shorted together and trip the safeties. We use metal bars for that but linesmen would need something that could be used for lines that are not always the same distance apart. I await a more informed response and hope you get one.
Were they Kellems grips?
No, they were braided cable bent into a “U” shape, resembling foot long hair pins.
I’m not sure what you are referring to so googled bucket truck in an image search I couldn’t find any that had the items as described.
I’ll keep my eyes out next time I see a truck
It is a distribution dead end grip a.k.a a preformed dead end. They distribute stress when attaching conductor to pole hardware.
Thanks, but I can’t see your pdf. 
Yes, that’s it.
I guess they take stress so that the connection doesn’t. How do they attach, are they crimped or tied?
Neither . . . the lineman uses several at once (nested against each other) and winds them around the end of the conductor. They operate on a similar, though not exactly the same principle as the Kellems grips mentioned above. They are manufactured in such a way as to have a very rough, sandpaper-like surface, which aids in the gripping.
I’m trying to think of an analogy . . .the best I can think of is this: imagine you have been asked to hold onto the rope for something that might be suddenly jerked away with a great force - a hot air balloon, or a large dog. You might be tempted to wind the rope around your forearm (this would be how the preform grip winds around the conductor), but it would be a bad idea because the winding configuration is deceptively strong. Bad if it is your arm, but good to hold onto wire.
And now that I think about it, maybe they are crimped after they are applied. But that wouldn’t be the primary force holding the wire.
They are used to attach two conductors together?
They can be used to do that (splicing), as seen here.
At my local utility (I work in the office, not the field, can you tell? 
), they are for attaching conductor at a pole, which you can see here if you zoom in a lot. The ends of the preform are wound around the end of the conductor, leaving the “U” portion at the other end unobstructed. That is attached via a clamp to an insulator, and the insulator is attached to the pole.
I’ll see if I can’t find some better pics when I am back in the office on Monday.
I understand. It reminds me of a pigtail splice, AKA Western Union splice, figure 5-30.
I’ve had other parts of much smaller gauge wire fail rather than the pigtail splice.
Thanks!
And thanks to you for asking about it. The ones I had seen were more like the Kellem grips engineer_comp_geek linked to but I find it all quite interesting.
One other thing is that they can be used when stringing conductor. The lineman can wind one or more around the end of the wire and use the “loop” as an attachment point for a boom hook. After the pulleys and starter line (nylon twine) are installed, you tie the twine to the loop and a few grunts pull the conductor up, through the pulleys, and back to the ground on the other side.
Untie the twine, pull the conductor to the next pole, and start again.