"Clean Room" ???????????????????? FRA looking over everyone's shoulder? What in the hell are you talking about?

It is the AAR, not the FRA, that creates the standards for a "Certified Air Brake Shop", and these standards apply to brake valves intended for interchange service. They operate in rooms that are clean, but hardly an industrial "clean room" enviroment like you see in the medical and electronics industry.

WABCO and NYAB did appear to coat the insides of some brake valves with a type of paint, but I do agree that it would be unusual for anyone to bead blast the valves and paint the inside surfaces. The problems are as someone pointed out - trying to removes every trace of the blast media, and if the paint was the wrong type or improperly applied, especially if it flaked off or otherwise restricted some of the passages.

My best guess is that UP 844 has schedule 8-ET, which is the predecessor to 24-RL and may have a few parts in common. WABCO will make limited runs of gaskets and some parts for obsolete valves, but is becoming increasingly reluctant and expensive to do so. While there are reputable air brake shops (and a few fly by night ones) that will do older brake valves, you would be extremely hard pressed to find anyone willing and able to do any 8 schedule. The biggest issues with pre 26/ABD brake valves is that they are all no less than 50 years old, sometimes much more, and are just plain worn out. Without extensive work to the slide valves and piston rings, plus having the proper test racks, they can't just be cleaned, lubed, reassembled and thrown back on an engine or car.

There really isn't much of the air system that can't be tested from a stationary air source, so unless the problem is with the air compressor or its lubrication, the rebuilt air brake system (including CCS interface) should have able to be fully tested before the engine was lit off.

The last I knew, there is no FRA requirement that locomotive or passenger brake valves be done by a certified or actual air brake shop. A shortline, museum or industrial can pull the valves off, clean and lube them, reinstall them and determine they are functioning properly. As long as they have done the work, and the brakes appear to be functioning properly, the FRA doesn't seem to care (at least at the moment). With the requirement to do older systems on an annual basis under FRA, many of the older brake valves on equipment in very limited service gets more wear and tear from the cleaning than the actual operation. Do keep in mind that very few of these systems have an air filter or drying systems, and pneumatic valves don't work well as a hydraulic version, especially when frozen.

THe basic problem today is far too few people have a real understanding of air brake systems, either for operation or maintenance.