Question about safety rails on older tower cranes in Seattle

I was up in Seattle last week walking by that big job site near the waterfront, and I noticed their older tower crane still has the old style bolt-on rails instead of the welded ones. The crew there said they've run it for 8 years without a single inspection flag, but my operator buddy in Portland has a hard rule against ever climbing one of those. So which is it, are the bolt-ons just as safe if you check the torque twice a shift, or is it a matter of time before one lets go? Has anyone else worked a rig like that and seen wear patterns in the bolt holes I should worry about?

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seana141mo ago

Used to be in the camp that bolt-ons were fine as long as you were on top of the torque checks. Then I watched a guy pull a rail right off a 20 year old rig when his lanyard caught during a swing, bolts were still in the holes, the steel around them was just gone. What changed my mind was learning how those holes elongate over time from stress cycles, so the torque reading lies to you because the bolt isn't actually clamping anything anymore. You can check it twice a shift and still miss it unless you're pulling bolts and looking at the holes with a light and a pick. Your Portland buddy's rule sounds strict but he's probably seen the same thing I did.

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