Turbo, back in 1970, you couldn't buy a membership in 324. You had to be born into the union. My brother got in, but his was a special deal he and the local worked out. I remember the union jobs around Saginaw then, you should have seen those old operators running the hard hitch 631A's and S24's. Their guts were hanging over their knees and many were wearing supports. Needless to say, the I-75 bypass wasn't built in a day with those guys.
In New Jersey, working on a emergency reservoir for PPL, 825 held sway and they ruled the roost. Just to move a light plant took 4 people in a medium flatbed truck. One Teamster to drive the truck. One Operating Engineer to start and stop the light
plant generator. One Electrician to flip the light switch on and off, and one Laborer to hook and unhook the light plant hitch to the truck. All the water pumps on the jobsite had their own Operating Engineer. The rock drills had an Operating Engineer and one Laborer. The Teamsters ran the parts trailer. I was supervision and as such, I could not pick up a shovel or a wrench lest I be time carded. I also could not tell any one Mechanic or Operator what to do. I had to tell the Operator Steward, or one of the three Master Mechanics what to do. They then told the others.
The union in Canada was the same way. You did not touch anyone else's work and there were strict rules laid out in the handbook about that. The Teamsters, Operating Engineers, and the 19 or so other unions at the US Steel works in Gary, Indiana were even worse.
I joined Local 9 in Colorado at age 33. I'd already been in the Teamster's and Carpenter's & Joiners. I signed up in Local 3 in California at age 49. I transferred that card to 428 in Arizona at age 59. I'm on a withdrawal now however.
I worked a job a year ago close to home that was a non-union project paying Davis-Bacon wages. Good money. The contractor is a double breasted outfit out of California. Every equipment operator on that job had a union card in their pocket from 428, 3, or 12. We could help out some with the laborers and the mechanics if we wanted or were able to, but we didn't have to. Depended on what crew you were on. Usually what happened if your rig went down was that you drove around with the foreman if it was late in the shift so you could get your 8 hours, or you went home. I didn't mind that in the least as I was just well enough to operate, but not in good enough shape to do anything else.
There is good and bad with these relationships everywhere, depending on how you are personally affected. I've been on every side of the fence there is. Most operators are in the same boat because you have to eat and keep the roof on over the family. You work non-union if you have to, but most would rather work union for the better pay and better benefits. But some folks do get a little carried away about it as I've outlined above. Every situation is different.