Big Boy 4014, a hydrostatic test, and why UP can beat the usual six month rule

Posted by Jim Wrinn
on Friday, February 8, 2019

Earlier this week, Union Pacific announced it has completed a successful hydrostatic test of the boiler on Big Boy No. 4014. That is the kind of news that says, “without doubt, this engine is going to run again, and soon.” Until you get that test completed, there’s still the potential for more boiler work. Once, it’s over, the heart of the engine is beating once more.

A hydrostatic test is required by the Federal Railroad Administration in which warm water in the boiler is raised to 25 percent above the maximum allowable working pressure. For Big Boy, the operating pressure is 300 psi. So, for the hydro test, the magic number is 375 psi. Why do we test boilers with water? It’s simple: Squeeze it with water and it leaks. Then you fix the leaks. Squeeze it with steam and the energy in the steam does bad things. Make sense?  

A general rule of thumb in rebuilding steam locomotives that have been dead for some time is that roughly six months after a successful hydro test, you’ll be up and running. If you have everything else done, wheels, running gear, appliances, tender, etc., you’ll be running in about six months after a good hydro. After the hydro, it’s connecting schedule 80 piping for air lines, running lube lines, bolting on various items. It’s the detailed work. It’s time consuming. Only a few people can fit into the work space. When you get to the last box of parts that you have no idea where they belong, you know you are done.

UP doesn’t have six months. The railroad and the steam crew want to debut their engine in early May to celebrate the 150th anniversary of the Golden Spike. In Ogden, Utah. 400 miles west of Cheyenne. They’re close, but they’ve still got a lot of work to do. Can they do it? Of course, they can. I haven’t been out to the shop at Cheyenne in several months and a planned visit late last month got cancelled due to weather, so I don’t have a current update other than what UP puts out. But I do know this: They’ve got a competent steam team that is smart and inspired. They’ve got a shop that’s been brought up to modern standards in recent years. They know how to work and work long and hard. They work ahead when they can. Best of all, they have the resources of the UP. One good thing about No. 4014’ largess: It’s big enough that you can spread out your workforce and attack several fronts at one time without getting in each other’s way.

This is not to minimize what’s ahead. Even doing a lot of work in advance, they’ve still got a lot more ahead of them. They’ve still got to get their oil firing burner up and running so they can test and adjust it. They’ve got to get a tender ready — I suspect that at this late date they’ll use Challenger No. 3985’s centipede tender, which is like 4014's but already fitted with an oil bunker. And they’ve got to get the whole rig out there to test, break in, and get ready for the big trip to Ogden come May.

Six months to running? Not this time. For Big Boy No. 4014, I am going to guess that we’ll see it test running around St. Patrick’s Day. If that happens, I’ll meet you at the John Galt Coffee Co., in Greeley, Colo., just down the street from the depot and the wye, where they’ll turn the engine. We can get a latte to toast the occasion — AFTER we take coffee to the crew and thank them for their hard work and completing in weeks what would take anyone else six months.

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