Why don't they lower the assembly to something like 5 feet so they can service it? They do that here.

I've seen them do that when the pole is off to the side. I guess they service it in a bucket for safety, the freeway it's on is one of the busiest in the world and not where I would want to stand when fixing a streetlight.

Here they use a crane and remove the whole highbay unit with pole, and place another one in it's place. The pole in then painted whilst on the ground and new lamps are installed and wired up before the whole unit is moved to the next lamp position to be installed.

I've seen them servicing highmasts from the ground, and it was on the 401 too. I think they usually group-relamp these so the reason the lights are turned on is because they need electricity to power the winches, here is an interesting video showing the operation of a low mast light, which is just a small high mast.

Here's a shot of the lowering controls inside a MTO highmast light.

This is a good way to service in in my opinion, since it's in the middle of the road.

How do those lowerign devices work? i guess in the days before electricity the lineman had to crank the cable by hand.

The video Niall linked to above describes it well...although it's for a smaller high mast light.

Ahh. i didn't even see the link when i read his comment. I never knew it involved that extra equippment. I thought you just put a key in and it activated the lowerign device similar to starting a car LOL. I've always thought highmasts were cool because they lowered like that. I also thought once the ring started lowering that the power was automatically cut to the lights.

I think the full size highmasts have the winch mounted inside the pole but the compact ones that Niall linked to didn't have room for the winch inside the pole and needed a external one.

That makes since. Seeing that the lowering devices are similar, I'm sure the user would only need one winch for a bunch LMS poles.

Actually the winches are optional, around here it seems most highmasts have them but you can get remote winches for these, I even once saw a trailer mounted winch that would be backed up to the pole and used. Quite a bit of information can be found here.

The days before electricity.. There WERE no high masts to crank! xD Most lights were ground level.

It was joke Ian...

Before holophane came around with lowering devices, that's probably what they did with the old arc lights.

Well yeah I know it was a joke, I was joking back.